Sample to Insight__
November 2020
RNeasy
®
Plus Micro
Handbook
For purification of total RNA using gDNA Eliminator columns from small samples,
includinganimal and human cells (≤5 x 10
5
),animal and human tissues (≤5 mg),microdissected
cryosections and for RNA cleanup and concentration
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Contents
Kit Contents ............................................................................................................... 4
Storage ..................................................................................................................... 4
Intended Use .............................................................................................................. 5
Safety Information ....................................................................................................... 5
Quality Control ........................................................................................................... 6
Introduction ................................................................................................................ 7
Principle and procedure .................................................................................... 8
Equipment and Reagents to Be Supplied by User .......................................................... 10
Important Notes ........................................................................................................ 11
Determining the amount of starting material ....................................................... 11
Handling and storing starting material .............................................................. 13
Disrupting and homogenizing starting material .................................................. 15
Carrier RNA .................................................................................................. 17
Limitations of small samples ............................................................................. 18
Automated purification of RNA on QIAcube Instruments ...................................... 19
Protocol: Purification of Total RNA from Animal and Human Cells .................................. 21
Protocol: Purification of Total RNA from Animal and Human Tissues ............................... 30
Protocol: Purification of Total RNA from Microdissected Cryosections .............................. 39
Troubleshooting Guide .............................................................................................. 45
Appendix A: General Remarks on Handling RNA......................................................... 49
Appendix B: Storage, Quantification and Determination of Quality of RNA .................... 52
Appendix C: RNA Cleanup and Concentration ............................................................ 56
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3
Appendix D: Purification of Total RNA Containing Small RNAs from Cells ....................... 57
Appendix E: Acetone Precipitation of Protein from Lysates ............................................. 60
Ordering Information ................................................................................................ 62
Document Revision History ......................................................................................... 66
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Kit Contents
RNeasy Plus Micro Kit
Catalog no.
Number of preps
(50)
74034
50
gDNA Eliminator Mini Spin Columns (uncolored)
(each in a 2 ml Collection Tube)
50
RNeasy MinElute
®
Spin Columns (pink)
(each in a 2 ml Collection Tube)
50
Collection Tubes (1.5 ml) 50
Collection Tubes (2 ml) 100
Buffer RLT Plus* 45 ml
Buffer RW1* 45 ml
Buffer RPE
(concentrate) 11 ml
RNase-Free Water 3 x 10 ml
Carrier RNA, poly-A 310 µg
Quick-Start Protocol 1
* Contains a guanidine salt. Not compatible with disinfectants containing bleach. See page 5 for safety information.
Before using for the first time, add 4 volumes of ethanol (96–100%) as indicated on the bottle to obtain a working
solution.
Storage
The RNeasy Plus Micro Kit is shipped at ambient temperature. Store the RNeasy MinElute spin
columns immediately upon receipt at 2–8ºC. Store the remaining components of the kit dry at
room temperature (15–25ºC). All kit components are stable for at least 9 months under these
conditions, if not otherwise stated on the label.
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5
Intended Use
The RNeasy Plus Micro Kit is intended for research use. No claim or representation is intended
to provide information for the diagnosis, prevention or treatment of a disease.
QIAcube
®
Connect is designed to perform fully automated purification of nucleic acids and
proteins in molecular biology applications. The system is intended for use by professional users
trained in molecular biological techniques and the operation of QIAcube Connect.
All due care and attention should be exercised in the handling of the products. We recommend
all users of QIAGEN
®
products to adhere to the NIH guidelines that have been developed for
recombinant DNA experiments or to other applicable guidelines.
Safety Information
When working with chemicals, always wear a suitable lab coat, disposable gloves and
protective goggles. For more information, please consult the appropriate safety data sheets
(SDSs). These are available online in convenient and compact PDF format at
www.qiagen.com/safety where you can find, view and print the SDS for each QIAGEN kit
and kit component.
CAUTION
CAUTION: DO NOT add bleach or acidic solutions directly to the sample-
preparation waste.
Buffer RLT Plus contains guanidine thiocyanate and Buffer RW1 contains a small amount of
guanidine thiocyanate. Guanidine salts can form highly reactive compounds when combined
with bleach. If liquid containing these buffers is spilt, clean with suitable laboratory detergent
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and water. If the spilt liquid contains potentially infectious agents, clean the affected area first
with laboratory detergent and water and then with 1% (v/v) sodium hypochlorite.
Quality Control
In accordance with QIAGEN’s ISO-certified Quality Management System, each lot of RNeasy
Plus Micro Kit is tested against predetermined specifications to ensure consistent product
quality.
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7
Introduction
The RNeasy Plus Micro Kit is designed to purify total RNA from small amounts of cells (as little
as 1 cell) or easy-to-lyse tissues. Suitable starting materials include laser-microdissected (LMD)
cryosections, fine-needle aspirates (FNA) and FACS
®
sorted cells. Genomic DNA
contamination is effectively removed using a specially designed gDNA Eliminator spin column.
The purified RNA is ready to use and is ideally suited for downstream applications that are
sensitive to low amounts of DNA contamination, such as quantitative, real-time RT-PCR.* The
purified RNA can also be used in other applications, including:
RT-PCR
Differential display
cDNA synthesis
Northern, dot and slot blot analyses
Primer extension
Poly A+ RNA selection
RNase/S1 nuclease protection
Microarrays
The RNeasy Plus Micro Kit allows the parallel processing of multiple samples in less than
30 minutes. Methods involving the use of toxic substances, such as phenol and/or chloroform,
or time-consuming and tedious methods, such as alcohol precipitation, are replaced by the
RNeasy Plus procedure.
* Visit www.qiagen.com/geneXpression for information on standardized solutions for gene expression analysis from
QIAGEN.
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Principle and procedure
The RNeasy Plus Micro procedure integrates QIAGEN’s technology for selective removal of
double-stranded DNA with well-established RNeasy MinElute technology. Efficient purification
of high-quality RNA in a small elution volume is guaranteed, without the need for additional
DNase digestion.
Biological samples are first lysed and homogenized in a highly denaturing guanidine-
isothiocyanate–containing buffer, which immediately inactivates RNases to ensure isolation of
intact RNA. The lysate is then passed through a gDNA Eliminator spin column. This column,
in combination with the optimized high-salt buffer, efficiently removes genomic DNA.
Ethanol is added to the flow-through to provide appropriate binding conditions for RNA, and
the sample is then applied to an RNeasy MinElute spin column, where total RNA binds to the
membrane and contaminants are efficiently washed away. High-quality RNA is then eluted in
as little as 14 µl of water.
With the RNeasy Plus Micro procedure, all RNA molecules longer than 200 nucleotides are
purified. The procedure enriches for mRNA, since most RNAs <200 nucleotides (such as 5.8S
rRNA, 5S rRNA and tRNAs, which together make up 15–20% of total RNA) are selectively
excluded. The size distribution of the purified RNA is comparable to that obtained by
centrifugation through a CsCl cushion, where small RNAs do not sediment efficiently. A
modification of the RNeasy Plus Micro procedure for cells allows the purification of total RNA
containing small RNAs, such as miRNA (see Appendix D, page 57).
In this handbook, different protocols are provided for different starting materials. The protocols
differ primarily in the lysis and homogenization of the sample. Once the sample is applied to
the gDNA Eliminator spin column, the protocols are similar (see flowchart, next page).
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9
RNeasy Plus Micro Procedure
Cells or tissue
Genomic DNA
Total RNA
Eluted RNA
Lyse and homogenize
Remove genomic DNA
Add ethanol
Bind total RNA
Wash
Elute
Total RNA
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Equipment and Reagents to Be Supplied by User
When working with chemicals, always wear a suitable lab coat, disposable gloves and
protective goggles. For more information, consult the appropriate safety data sheets (SDSs),
available from the product supplier.
14.3 M β-mercaptoethanol (β-ME) (commercially available solutions are usually 14.3 M)
or, alternatively, 2 M dithiothreitol (DTT) in water
Ethanol (70% and 96–100%)*
Sterile, RNase-free pipet tips
Microcentrifuge (with rotor for 2 ml tubes)
Vortexer
Disposable gloves
Reagent for RNA stabilization (see page 13):
For cell samples: RNAprotect
®
Cell Reagent
or liquid nitrogen
For tissue samples: RNAprotect Tissue Reagent
(stabilizes RNA only), Allprotect
®
Tissue Reagent
(stabilizes DNA, RNA and protein) or liquid nitrogen
Equipment for sample disruption and homogenization (see pages 15–17). Depending on
the method chosen, one or more of the following are required:
Trypsin and PBS
QIAshredder homogenizer
Blunt-ended needle and syringe
Mortar and pestle
TissueRuptor II with TissueRuptor Disposable Probes
TissueLyser II
* Do not use denatured alcohol, which contains other substances, such as methanol or methylethylketone.
For ordering information, see page 50.
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11
Important Notes
Determining the amount of starting material
It is essential to use the correct amount of starting material to obtain optimal RNA yield and
purity. The maximum amount that can be used is determined by:
The type of sample and its RNA content
The volume of Buffer RLT Plus required for efficient lysis
The DNA removal capacity of the gDNA Eliminator spin column
The RNA binding capacity of the RNeasy MinElute spin column
When processing samples containing high amounts of DNA or RNA, less than the maximum
amount of starting material shown in Table 1 should be used, so that the DNA removal
capacity of the gDNA Eliminator spin column and the RNA binding capacity of the RNeasy
MinElute spin column are not exceeded.
When processing samples containing average or low amounts of RNA, the maximum amount
of starting material shown in Table 1 can be used. However, even though the RNA binding
capacity of the RNeasy MinElute spin column is not reached, the maximum amount of starting
material must not be exceeded. Otherwise, lysis will be incomplete and cellular debris may
interfere with the binding of RNA to the RNeasy spin column membrane, resulting in lower
RNA yield and purity.
More information on using the correct amount of starting material is given in each protocol.
Table 2 shows typical RNA yields from various cells and tissues.
Note: If the DNA removal capacity of the gDNA Eliminator spin column is exceeded, the
purified RNA will be contaminated with DNA. Although the gDNA Eliminator spin column can
bind more than 100 µg DNA, we recommend using samples containing less than 20 µg DNA
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to ensure removal of virtually all genomic DNA. If the binding capacity of the RNeasy MinElute
spin column is exceeded, RNA yields will not be consistent and may be reduced. If lysis of the
starting material is incomplete, RNA yields will be lower than expected, even if the binding
capacity of the RNeasy MinElute spin column is not exceeded.
Table 1. RNeasy MinElute spin column specifications
Maximum binding capacity 45 µg RNA
Maximum loading volume
700 µl
RNA size distribution
RNA >200 nucleotides*
Minimum elution volume
14 µl
Maximum amount of starting material
Animal and human cells
5 x 10
5
Animal and human tissues
5 mg
* Purification of total RNA containing small RNAs from cells is possible through a modification of the RNeasy Plus
Micro procedure. For details, see Appendix D, page 57.
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13
Table 2. Typical yields of total RNA with the RNeasy Plus Micro Kit
Sample type Yield of total RNA* (µg)
Cell cultures (5 x 10
5
cells)
NIH/3T3 5
HeLa 7.5
COS-7 17.5
LMH 6
Huh 7.5
Mouse/rat tissues (5 mg)
Embryo (13 day) 10
Brain 2–5
Kidney 10–15
Liver 20–30
Spleen 15–20
Thymus 20–25
Lung 5–10
* Amounts can vary due to factors, such as species, developmental stage and growth conditions. Since the RNeasy
Plus Micro procedure enriches for mRNA and other RNA species >200 nucleotides, the total RNA yield does not
include 5S rRNA, tRNA and other low-molecular-weight RNAs, which make up 15–20% of total cellular RNA.
Handling and storing starting material
Cells
After harvesting, cells should be immediately lysed in Buffer RLT Plus to prevent unwanted
changes in the gene expression profile. This highly denaturing lysis buffer inactivates RNases
and other proteins to prevent RNA degradation as well as downregulation or upregulation of
transcripts.
If the cells are to be shipped to another lab for RNA purification, they should be pelleted,
frozen in liquid nitrogen and transported on dry ice. Alternatively, the cells can be mixed with
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RNAprotect Cell Reagent at room temperature (15–25ºC) and then shipped at ambient
temperature.
Tissues
RNA in harvested tissue is not protected until the sample is treated with RNAprotect Tissue
Reagent, flash-frozen or disrupted and homogenized in the presence of RNase-inhibiting or
denaturing reagents. Otherwise, unwanted changes in the gene expression profile will occur.
It is therefore important that tissue samples are immediately frozen in liquid nitrogen and stored
at –90°C to –65°C or immediately immersed in RNAprotect Tissue Reagent. An alternative to
RNAprotect Tissue Reagent is Allprotect Tissue Reagent, which provides immediate
stabilization of DNA, RNA and protein in tissue samples at room temperature (15–25ºC).
The procedures for tissue harvesting and RNA protection should be carried out as quickly as
possible. Frozen tissue samples should not be allowed to thaw during handling or weighing.
After disruption and homogenization in Buffer RLT Plus (lysis buffer), samples can be stored at
–90°C to –65°C for months.
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15
Disrupting and homogenizing starting material
Efficient disruption and homogenization of the starting material is an absolute requirement for
all total RNA purification procedures. Disruption and homogenization are 2 distinct steps.
Disruption: Complete disruption of plasma membranes of cells and organelles is
absolutely required to release all the RNA contained in the sample. Different samples
require different methods to achieve complete disruption. Incomplete disruption results in
significantly reduced RNA yields.
Homogenization: Homogenization is necessary to reduce the viscosity of the lysates
produced by disruption. Homogenization shears the high-molecular-weight genomic
DNA and other high-molecular-weight cellular components to create a homogeneous
lysate. Incomplete homogenization results in inefficient binding of RNA to the RNeasy
MinElute spin column membrane and therefore significantly reduced RNA yields.
Some disruption methods simultaneously homogenize the sample, while others require an
additional homogenization step. Table 3 gives an overview of different disruption and
homogenization methods, and is followed by a detailed description of each method.
Table 3. Disruption and homogenization methods
Sample Disruption method Homogenization method
Microdissected samples Addition of lysis buffer Vortexing
Cells and fine- needle aspirates (FNA) Addition of lysis buffer TissueRuptor II or QIAshredder
homogenizer or syringe and needle*
Tissues TissueRuptor II
TissueLyser II
Mortar and pestle
§
TissueRuptor II
TissueLyser II
QIAshredder homogenizer or syringe and
needle
* If processing ≤1 x 10
5
cells, the lysate can be homogenized by vortexing.
Simultaneously disrupts and homogenizes individual samples.
Simultaneously disrupts and homogenizes up to 192 samples in parallel. Results are comparable to those obtained
using the TissueRuptor II or other rotor–stator homogenizer.
§
The TissueRuptor and TissueLyser II usually give higher RNA yields than mortar and pestle.
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Disruption and homogenization using the TissueRuptor II
The TissueRuptor II is a rotor–stator homogenizer that thoroughly disrupts and simultaneously
homogenizes single tissue samples in the presence of lysis buffer in 15–90 seconds, depending
on the toughness and size of the sample. The TissueRuptor II can also be used to homogenize
cell lysates. The blade of the TissueRuptor disposable probe rotates at a very high speed,
causing the sample to be disrupted and homogenized by a combination of turbulence and
mechanical shearing. For guidelines on using the TissueRuptor II, refer to the TissueRuptor II
Handbook. For other rotor–stator homogenizers, refer to suppliers’ guidelines.
Disruption and homogenization using the TissueLyser II
In bead-milling, tissues can be disrupted by rapid agitation in the presence of beads and lysis
buffer. Disruption and simultaneous homogenization occur by the shearing and crushing action
of the beads as they collide with the cells. The TissueLyser II disrupts and homogenizes up to
48 tissue samples simultaneously when used in combination with the TissueLyser Adapter Set
2 x 24, which holds 48 x 2 ml microcentrifuge tubes containing stainless steel beads of 5 mm
mean diameter. The TissueLyser II can also disrupt and homogenize up to 192 tissue samples
simultaneously when used in combination with the TissueLyser Adapter Set 2 x 96, which holds
192 x 1.2 ml microtubes containing stainless steel beads of 5 mm mean diameter. For
guidelines on using the TissueLyser II, refer to the TissueLyser II Handbook. For other bead
mills, refer to suppliers’ guidelines.
Note: Tungsten carbide beads react with Buffer RLT Plus and must not be used to disrupt and
homogenize tissues.
Disruption using a mortar and pestle
For disruption using a mortar and pestle, freeze the tissue sample immediately in liquid
nitrogen and grind to a fine powder under liquid nitrogen. Transfer the suspension (tissue
powder and liquid nitrogen) into a liquid-nitrogen–cooled, appropriately sized tube and allow
the liquid nitrogen to evaporate without allowing the sample to thaw. Add lysis buffer and
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17
continue as quickly as possible with the homogenization according to one of the 2 methods
below.
Note: Grinding the sample using a mortar and pestle will disrupt the sample, but will not
homogenize it. Homogenization must be performed afterwards.
Homogenization using QIAshredder homogenizers
Using QIAshredder homogenizers is a fast and efficient way to homogenize cell and tissue
lysates without cross-contamination of samples. Up to 700 µl of lysate is loaded onto a
QIAshredder spin column placed in a 2 ml collection tube, and spun for 2 minutes at maximum
speed in a microcentrifuge. The lysate is homogenized as it passes through the spin column.
Homogenization using a syringe and needle
Cell and tissue lysates can be homogenized using a syringe and needle. Lysate is passed
through a 20-gauge (0.9 mm) needle attached to a sterile plastic syringe at least 5–10 times
or until a homogeneous lysate is achieved. Increasing the volume of lysis buffer may be
required to facilitate handling and minimize loss.
Carrier RNA
The RNeasy Plus Micro Kit contains poly-A RNA for use as carrier RNA. When added to
lysates from very small samples, the carrier RNA may in some cases improve the recovery of
total RNA. Carrier RNA is not required when processing more than 500 cells or more than
about 2 µg tissue.
As demonstrated in many different RT-PCR systems, the small amounts of poly-A RNA used as
carrier RNA in total RNA purification do not interfere with subsequent RT-PCR, even when
oligo-dT is used as a primer for reverse transcription. Reverse-transcription reactions typically
contain an excess of oligo-dT primers, and the small amounts of poly-A used as carrier RNA
are insignificant in comparison.
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However, total RNA purified using poly-A RNA as carrier RNA is not compatible with protocols
to amplify mRNA transcripts using oligo-dT primers. These include the Eberwine method and
the QuantiTect
®
Whole Transcriptome Kit (the kit uses a mix of random and oligo-dT primers).
For the Eberwine method, other types of RNA can be purchased separately for use as carrier
RNA. Note, however, that tRNA and other RNAs <200 nucleotides will not bind to the RNeasy
MinElute membrane and cannot be used as carrier RNA. For most applications, bacterial
ribosomal RNA (e.g., from Roche, cat. no. 206938)* gives good results and can be used as
an alternative to the poly-A RNA supplied with this kit. However, if amplifying mRNA
transcripts with the QuantiTect Whole Transcriptome Kit, no carrier RNA of any type should
be used in RNA purification.
Limitations of small samples
When purifying nucleic acids from particularly small samples (e.g., laser-microdissected
samples), the amounts of RNA may be too small for quantification by spectrophotometry or
even fluorometric assays. In this case, quantitative, real-time RT-PCR should be used for
quantification.
When purifying RNA from less than 100 cells, stochastic problems with respect to copy number
can occur. This is because some RNA transcripts may be present at very low copy numbers
per cell, or only in a fraction of all cells in the sample of interest. For example, if a particular
RNA transcript is present at an abundance of 1 copy per cell, and 10 cells are processed with
RNA eluted in the recommended volume of 14 µl, there will be less than 1 copy of the transcript
per microliter.
Whole transcriptome amplification can be carried out to generate sufficient amounts of RNA
if several downstream assays need to be performed from a single small sample. However,
care should be taken to include a sufficient amount of starting material in the amplification
* This is not a complete list of suppliers and does not include many important vendors of biological supplies. When
working with chemicals, always wear a suitable lab coat, disposable gloves and protective goggles. For more
information, consult the appropriate safety data sheets (SDSs), available from the product supplier.
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19
reaction to avoid stochastic problems. The QuantiTect Whole Transcriptome Kit provides
highly uniform amplification of the transcriptome.
Automated purification of RNA on QIAcube Instruments
Purification of RNA can be fully automated on QIAcube Connect or the classic QIAcube. The
innovative QIAcube instruments use advanced technology to process QIAGEN spin columns,
enabling seamless integration of automated, low-throughput sample prep into your laboratory
workflow. Sample preparation using QIAcube instruments follows the same steps as the
manual procedure (i.e., lyse, bind, wash and elute), enabling you to continue using the
RNeasy Plus Micro Kit for purification of high-quality RNA.
QIAcube instruments are preinstalled with protocols for purification of plasmid DNA, genomic
DNA, RNA, viral nucleic acids and proteins, plus DNA and RNA cleanup. The range of
protocols available is continually expanding, and additional QIAGEN protocols can be
downloaded free of charge at www.qiagen.com/qiacubeprotocols.
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QIAcube Connect.
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21
Protocol: Purification of Total RNA from Animal
and Human Cells
Determining the correct amount of starting material
It is essential to use the correct amount of starting material to obtain optimal RNA yield and
purity. The maximum amount depends on:
The RNA content of the cell type
The DNA removal capacity of the gDNA Eliminator spin column
The RNA binding capacity of the RNeasy MinElute spin column (45 µg RNA)
The volume of Buffer RLT Plus required for efficient lysis
In addition, cellular debris can reduce the binding capacity of the gDNA Eliminator and
RNeasy MinElute spin columns. If processing a cell type not listed in Table 2 (page 13) and if
there is no information about its RNA content, we recommend starting with no more than
5 x 10
5
cells.
Do not overload the gDNA Eliminator spin column, as this will lead to copurification
of DNA with RNA. Do not overload the RNeasy MinElute spin column, as this will
significantly reduce RNA yield and purity.
Counting cells is the most accurate way to quantitate the amount of starting material. As a
guide, the number of HeLa cells obtained in various culture vessels after confluent growth is
given in Table 4.
Important points before starting
If using the RNeasy Plus Micro Kit for the first time, read “Important Notes” (page 11).
If preparing RNA for the first time, read Appendix A (page49).
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If using the TissueRuptor II, ensure that you are familiar with operating it by referring to
the TissueRuptor II User Manual and TissueRuptor II Handbook.
Cell pellets can be stored at –90°C to –65°C for later use or used directly in the
procedure. Determine the number of cells before freezing. Frozen cell pellets should be
thawed slightly so that they can be dislodged by flicking the tube in step 2.
Homogenized cell lysates from step 3 can be stored at –90°C to –65°C for several
months. Frozen lysates should be incubated at 37ºC in a water bath until completely
thawed and salts are dissolved. Avoid prolonged incubation, which may compromise
RNA integrity. If any insoluble material is visible, centrifuge for 5 min at 3000–5000 x g.
Transfer the supernatant to a new RNase-free glass or polypropylene tube, and continue
with step 4.
Table 4. Growth area and number of HeLa cells in various culture vessels
Cell-culture vessel Growth area (cm
3
)* Number of cells
Multiwell plates
96-well 0.32–0.6 4–5 x 10
4
48-well 1 1 x 10
5
24-well 2 2.5 x 10
5
12-well 4 5 x 10
5
6-well 9.5 1 x 10
6‡
Dishes
35 mm 8 1 x 10
6‡
Flasks
40–50 ml 25 3 x 10
6‡
* Per well, if multiwell plates are used; varies slightly depending on the supplier.
Cell numbers are given for HeLa cells (approximate length = 15 µm), assuming confluent growth. Numbers will vary
for different kinds of animal and human cells, which vary in length from 10 to 30 µm.
This number of cells exceeds the maximum binding capacity of the RNeasy MinElute spin columns. To process this
many cells, split the lysate into appropriate aliquots (≤5 x 10
5
cells each) and load them onto separate RNeasy
MinElute spin columns.
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23
Cells stored in RNAprotect Cell Reagent can also be used in the procedure. Transfer the
entire sample, including any material deposited at the bottom of the storage vessel, to a
centrifuge tube. Pellet the cells by centrifuging for 5 min at 5000 x g, and remove the
supernatant by pipetting (if necessary, thaw the sample before centrifuging). Proceed
immediately to step 2.
Buffer RLT Plus and Buffer RW1 contain a guanidine salt and are therefore not
compatible with disinfecting reagents containing bleach. See page 5 for safety
information.
Perform all steps of the procedure at room temperature (15–25ºC). During the procedure,
work quickly.
Perform all centrifugation steps at 20–25ºC in a standard microcentrifuge. Ensure that the
centrifuge does not cool below 20ºC.
Things to do before starting
If purifying RNA from cell lines rich in RNases, we recommend adding
β-mercaptoethanol (β-ME) to Buffer RLT Plus before use. Add 10 µl β-ME per 1 ml Buffer
RLT Plus. Dispense in a fume hood and wear appropriate protective clothing. Buffer RLT
Plus containing β-ME can be stored at room temperature (15–25ºC) for up to 1 month.
Alternatively, add 20 µl of 2 M dithiothreitol (DTT) per 1 ml Buffer RLT Plus. The stock
solution of 2 M DTT in water should be prepared fresh or frozen in single-use aliquots.
Buffer RLT Plus containing DTT can be stored at room temperature for up to 1 month.
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When processing <500 cells, carrier RNA may be added to the lysate before
homogenization (see “Carrier RNA”, page17). Before using for the first time, dissolve
the carrier RNA (310 µg) in 1 ml RNase-free water. Store this stock solution at –30°C
to –15°C , and use it to make fresh dilutions for each set of RNA preps. The
concentration of this stock solution is 310 µg/ml (i.e., 310 ng/µl). To make a working
solution (4 ng/µl) for 10 preps, add 5 µl stock solution to 34 µl Buffer RLT Plus and mix
by pipetting. Add 6 µl of this diluted solution to 54 µl Buffer RLT Plus to give a working
solution of 4 ng/µl. Add 5 µl of this solution to the lysate in step 3. Do not add the
carrier RNA to the lysate if purifying RNA for use in oligo-dT–based
amplification.
Buffer RPE is supplied as a concentrate. Before using for the first time, add 4 volumes of
ethanol (96–100%) as indicated on the bottle to obtain a working solution.
Before using the kit for the first time, prepare 80% ethanol by mixing 24 ml ethanol
(96–100%) and 6 ml RNase-free water (supplied). The procedure also requires 70%
ethanol, which can be prepared by diluting ethanol (96–100%) with distilled water (not
supplied).
Buffer RLT Plus may form a precipitate during storage. If necessary, redissolve by
warming, and then place at room temperature.
Procedure
1. Harvest cells according to step 1a or 1b.
1a. Cells grown in suspension (do not use more than 5 x 10
5
cells):
Determine the number of cells. Pellet the appropriate number of cells by centrifuging
for 5 min at 300 x g in a centrifuge tube (not supplied). Carefully remove all
supernatant by aspiration, and proceed to step 2.
Note: Incomplete removal of cell-culture medium will inhibit lysis and dilute the
lysate, affecting the conditions for DNA removal and RNA purification. Both effects
may reduce RNA yield and purity.
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25
1b. Cells grown in a monolayer (do not use more than 5 x 10
5
cells):
Cells grown in a monolayer in cell-culture vessels can be either lysed directly in the
vessel (up to 10 cm diameter) or trypsinized and collected as a cell pellet prior to
lysis. Cells grown in a monolayer in cell-culture flasks should always be trypsinized.
To lyse cells directly:
Determine the number of cells. Completely aspirate the cell-culture medium, and
proceed immediately to step 2.
Note: Incomplete removal of cell-culture medium will inhibit lysis and dilute the
lysate, affecting the conditions for DNA removal and RNA purification. Both effects
may reduce RNA yield and purity.
To trypsinize and collect cells:
Determine the number of cells. Aspirate the medium, and wash the cells with PBS.
Aspirate the PBS, and add 0.10–0.25% trypsin in PBS. After the cells detach from
the dish or flask, add medium (containing serum to inactivate the trypsin), transfer
the cells to an RNase-free glass or polypropylene centrifuge tube (not supplied),
and centrifuge at 300 x g for 5 min. Completely aspirate the supernatant, and
proceed to step 2.
Note: Incomplete removal of cell-culture medium will inhibit lysis and dilute the
lysate, affecting the conditions for DNA removal and RNA purification. Both effects
may reduce RNA yield and purity.
2. Disrupt the cells by adding Buffer RLT Plus.
For pelleted cells, loosen the cell pellet thoroughly by flicking the tube. Add 350 µl
Buffer RLT Plus. Vortex or pipet to mix, and proceed to step 3.
If processing ≤1 x 10
5
cells, 75 µl Buffer RLT Plus can be added instead. This allows cell
pelleting in smaller tubes. Pipet up and down to lyse the cells.
Note: Incomplete loosening of the cell pellet may lead to inefficient lysis and reduced
RNA yields.
For direct lysis of cells grown in a monolayer, add 350 µl Buffer RLT Plus to the cell-
culture dish. Collect the lysate with a rubber policeman. Pipet the lysate into a
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RNeasy Plus Micro Handbook
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microcentrifuge tube (not supplied). Vortex or pipet to mix, and ensure that no cell clumps
are visible before proceeding to step 3.
If processing ≤1 x 10
5
cells, 75 µl Buffer RLT Plus can be added instead. This may be
necessary for multiwell plates and cell-culture dishes. Pipet up and down to lyse the cells.
3. Homogenize the lysate according to step 3a, 3b or 3c.
See “Disrupting and homogenizing starting material”, page 15, for more details on
homogenization. If processing ≤1 x 10
5
cells, they can be homogenized by vortexing for
1 min. After homogenization, proceed to step 4.
Note: If only 75 µl Buffer RLT Plus was used in step 2, transfer the lysate to a new 1.5 ml
microcentrifuge tube, and adjust the volume to 350 µl with Buffer RLT Plus. Vortex for
1 min to homogenize and proceed to step 4.
Note: If processing <500 cells, 20 ng carrier RNA (5 µl of a 4 ng/µl solution) may be
added to the lysate before homogenization. Prepare the carrier RNA as described in
“Things to do before starting”.
Note: Incomplete homogenization leads to significantly reduced RNA yields and can
cause clogging of the gDNA Eliminator and RNeasy MinElute spin columns.
Homogenization with the TissueRuptor or QIAshredder homogenizer generally results in
higher RNA yields than with a syringe and needle.
3a. Pipet the lysate directly into a QIAshredder spin column (not supplied) placed in a
2 ml collection tube, and centrifuge for 2 min at full speed. Proceed to step 4.
3b. Place the tip of the TissueRuptor disposable probe into the lysate and operate the
TissueRuptor at full speed until the lysate is homogenous (usually 30 s). Proceed to
step 4.
Note: To avoid damage to the TissueRuptor II and disposable probe during
operation, make sure the tip of the probe remains submerged in the buffer.
3c. Pass the lysate at least 5 times through a blunt 20-gauge needle (0.9 mm diameter)
fitted to an RNase-free syringe. Proceed to step 4.
RNeasy Plus Micro Handbook
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27
4. Transfer the homogenized lysate to a gDNA Eliminator spin column placed in a 2 ml
collection tube (supplied). Centrifuge for 30 s at ≥8000 x g (≥10,000 rpm). Discard the
column, and save the flowthrough.
Note: Make sure that no liquid remains on the column membrane after centrifugation. If
necessary, repeat the centrifugation until all liquid has passed through the membrane.
The remaining steps of this protocol allow the purification of RNA molecules longer than
200 nucleotides. If purification of total RNA containing small RNAs, such as miRNA is
desired, follow steps 1–6 in Appendix D on page 57 instead of steps 5–11 in this
protocol.
5. Add 1 volume (usually 350 µl) of 70% ethanol to the flow-through from step 4, and mix
well by pipetting. Do not centrifuge. Proceed immediately to step 6.
Note: The volume of 70% ethanol to add may be less than 350 µl if some lysate was lost
during homogenization and DNA removal.
Note: When purifying RNA from certain cell lines, precipitates may be visible after
addition of ethanol. This does not affect the procedure.
6. Transfer the sample, including any precipitate that may have formed, to an RNeasy
MinElute spin column placed in a 2 ml collection tube (supplied). Close the lid gently,
and centrifuge for 15 s at ≥8000 x g (≥10,000 rpm). Discard the flow-through.*
Optional: If recovery of protein is desired, keep the flow-through on ice and follow
steps 1–5 in Appendix E on page 60.
Reuse the collection tube in step 7.
* Flow-through contains Buffer RLT Plus or Buffer RW1 and is therefore not compatible with bleach. See page 6 for
safety information.
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7. Add 700 µl Buffer RW1 to the RNeasy MinElute spin column. Close the lid gently, and
centrifuge for 15 s at ≥8000 x g (≥10,000 rpm) to wash the spin column membrane.
Discard the flow-through.*
Reuse the collection tube in step 8.
Note: After centrifugation, carefully remove the RNeasy MinElute spin column from the
collection tube so that the column does not contact the flow-through. Be sure to empty the
collection tube completely.
8. Add 500 µl Buffer RPE to the RNeasy MinElute spin column. Close the lid gently, and
centrifuge for 15 s at ≥8000 x g (≥10,000 rpm) to wash the spin column membrane.
Discard the flow-through.
Reuse the collection tube in step 9.
Note: Buffer RPE is supplied as a concentrate. Ensure that ethanol is added to Buffer RPE
before use (see “Things to do before starting”).
9. Add 500 µl of 80% ethanol to the RNeasy MinElute spin column. Close the lid gently,
and centrifuge for 2 min at ≥8000 x g (≥10,000 rpm) to wash the spin column
membrane. Discard the collection tube with the flow-through.
Prepare the 80% ethanol with ethanol (96–100%) and the RNase-free water supplied
with the kit.
Note: After centrifugation, carefully remove the RNeasy MinElute spin column from the
collection tube so that the column does not contact the flow-through. Otherwise,
carryover of ethanol will occur.
RNeasy Plus Micro Handbook
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29
10. Place the RNeasy MinElute spin column in a new 2 ml collection tube (supplied). Open
the lid of the spin column, and centrifuge at full speed for 5 min. Discard the collection
tube with the flow-through.
To avoid damage to their lids, place the spin columns into the centrifuge with at least one
empty position between columns. Orient the lids so that they point in a direction opposite
to the rotation of the rotor (e.g., if the rotor rotates clockwise, orient the lids
counterclockwise).
It is important to dry the spin column membrane, since residual ethanol may interfere with
downstream reactions. Centrifugation with the lids open ensures that no ethanol is
carried over during RNA elution.
11. Place the RNeasy MinElute spin column in a new 1.5 ml collection tube (supplied). Add
14 µl RNase-free water directly to the center of the spin column membrane. Close the lid
gently, and centrifuge for 1 min at full speed to elute the RNA.
As little as 10 µl RNase-free water can be used for elution if a higher RNA concentration
is required, but the yield will be reduced by approximately 20%. Do not elute with less
than 10 µl RNase-free water, as the spin column membrane will not be sufficiently
hydrated.
The dead volume of the RNeasy MinElute spin column is 2 µl: elution with 14 µl RNase-
free water results in a 12 µl eluate.
For RT-PCR and real-time RT-PCR with the purified RNA, QIAGEN offers a range of
optimized, ready-to-use kits that provide highly specific and sensitive results. For details,
visit www.qiagen.com/PCR. For whole transcriptome amplification (WTA) of limited
amounts of RNA, we recommend the QuantiTect Whole Transcriptome Kit.
30
RNeasy Plus Micro Handbook
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Protocol: Purification of Total RNA from Animal
and Human Tissues
This protocol is for the purification of total RNA from easy-to-lyse animal and human tissues.
For total RNA purification from frozen, microdissected tissue samples, see page 39.
Determining the correct amount of starting material
It is essential to use the correct amount of starting material to obtain optimal RNA yield and
purity. A maximum amount of 5 mg fresh or frozen tissue or 2–3 mg RNAprotect- or Allprotect-
stabilized tissue (which is partially dehydrated) can generally be processed. For most tissues,
the DNA removal capacity of the gDNA Eliminator spin column, the RNA binding capacity of
the RNeasy MinElute spin column and the lysing capacity of Buffer RLT Plus will not be exceeded
by these amounts. Typical RNA yields from various tissues are given in Table 2 (page 13).
For maximum RNA yields from liver, 50% ethanol (instead of 70% ethanol) should be used in
step 4 of the procedure.
Some tissues, such as spleen, parts of brain, lung and thymus, tend to form precipitates during
the procedure. However, this does not affect RNA purification.
Do not overload the gDNA Eliminator spin column, as this will lead to copurification
of DNA with RNA. Do not overload the RNeasy MinElute spin column, as this will
significantly reduce RNA yield and quality.
Weighing tissue is the most accurate way to quantitate the amount of starting material. As a
guide, a 1.5 mm cube (3.4 mm
3
) of most animal tissues weighs 3.5–4.5 mg.
RNeasy Plus Micro Handbook
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31
Important points before starting
If using the RNeasy Plus Micro Kit for the first time, read “Important Notes” (page 11).
If preparing RNA for the first time, read Appendix A (page 49).
If using the TissueRuptor II, ensure that you are familiar with operating it by referring to
the TissueRuptor II User Manual and TissueRuptor II Handbook.
If using the TissueLyser, ensure that you are familiar with operating it by referring to the
operating instructions and TissueLyser II Handbook.
For optimal results, stabilize harvested tissues immediately in RNAprotect Tissue Reagent
(see the RNAprotect Handbook) or Allprotect Tissue Reagent (see the Allprotect Tissue
Reagent Handbook). Tissues can be stored in the reagent at 37ºC for up to 1 day, at
15–25ºC for up to 7 days, or at 2–8ºC for up to 4 weeks (RNAprotect) or 6 months
(Allprotect). Alternatively, tissues can be archived at –30°C to –15°C or –90°C to –65°C.
Fresh, frozen or RNAprotect- or Allprotect-stabilized tissue can be used. Tissues can be
stored at –90°C to –65°C for several months. Flash-freeze tissues in liquid nitrogen, and
immediately transfer to –90°C to –65°C. Do not allow tissues to thaw during weighing or
handling prior to disruption in Buffer RLT Plus. Homogenized tissue lysates from step 2
can also be stored at –90°C to –65°C for several months. Incubate frozen lysates at
37ºC in a water bath until completely thawed and salts are dissolved before continuing
with step 3. Avoid prolonged incubation, which may compromise RNA integrity.
Buffer RLT Plus and Buffer RW1 contain a guanidine salt and are therefore not
compatible with disinfecting reagents containing bleach. See page 5 for safety
information.
Perform all steps of the procedure at room temperature (15–25ºC). During the procedure,
work quickly.
Perform all centrifugation steps at 20–25ºC in a standard microcentrifuge. Ensure that the
centrifuge does not cool below 20ºC.
32
RNeasy Plus Micro Handbook
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Things to do before starting
β-Mercaptoethanol (β-ME) must be added to Buffer RLT Plus before use. Add 10 µl β-ME
per 1 ml Buffer RLT Plus. Dispense in a fume hood and wear appropriate protective
clothing. Buffer RLT Plus containing β-ME can be stored at room temperature (15–25ºC)
for up to 1 month. Alternatively, add 20 µl of 2 M dithiothreitol (DTT) per 1 ml Buffer RLT
Plus. The stock solution of 2 M DTT in water should be prepared fresh or frozen in single-
use aliquots. Buffer RLT Plus containing DTT can be stored at room temperature for up to
1 month.
When processing less than about 2 µg tissue, carrier RNA may be added to the lysate
before homogenization (see “Carrier RNA”, page 17). Before using for the first time,
dissolve the carrier RNA (310 µg) in 1 ml RNase-free water. Store this stock solution at
–30°C to –15°C, and use it to make fresh dilutions for each set of RNA preps. The
concentration of this stock solution is 310 µg/ml (i.e., 310 ng/µl). To make a working
solution (4 ng/µl) for 10 preps, add 5 µl stock solution to 34 µl Buffer RLT Plus and mix
by pipetting. Add 6 µl of this diluted solution to 54 µl Buffer RLT Plus to give a working
solution of 4 ng/µl. Add 5 µl of this solution to the lysate in step 2. Do not add the
carrier RNA to the lysate if purifying RNA for use in oligo-dT–based
amplification.
Buffer RPE is supplied as a concentrate. Before using for the first time, add 4 volumes of
ethanol (96–100%) as indicated on the bottle to obtain a working solution.
Before using the kit for the first time, prepare 80% ethanol by mixing 24 ml ethanol
(96–100%) and 6 ml RNase-free water (supplied). The procedure also requires 70%
ethanol, which can be prepared by diluting ethanol (96–100%) with distilled water (not
supplied).
Buffer RLT Plus may form a precipitate during storage. If necessary, redissolve by
warming and then place at room temperature.
RNeasy Plus Micro Handbook
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33
Procedure
Excise the tissue sample from the animal or remove it from storage. Determine the amount
of tissue. Do not use more than 5 mg. Proceed immediately to step 2.
Weighing tissue is the most accurate way to determine the amount. If necessary, cut the
tissue on a clean surface and weigh the piece to be used.
For RNAprotect- or Allprotect-stabilized tissues: Remove the tissue from the
stabilization reagent using forceps and be sure to remove any crystals that may have
formed. RNA in RNAprotect- or Allprotect-stabilized tissues is protected during cutting
and weighing of tissues at ambient temperature (15–25ºC). It is not necessary to cut the
tissues on ice or dry ice or in a refrigerated room. Remaining tissues can be stored in
RNAprotect Tissue Reagent or Allprotect Reagent. Previously stabilized tissues can be
stored at –90°C to –65°C without the reagent.
For unstabilized fresh or frozen tissues: RNA in harvested tissues is not protected
until the tissues are treated with RNAprotect Tissue Reagent or Allprotect Reagent, flash-
frozen or disrupted and homogenized in step 2. Frozen tissues should not be allowed to
thaw during handling. The relevant procedures should be carried out as quickly as
possible. Remaining fresh tissues can be placed into RNAprotect Tissue Reagent to
stabilize RNA or in Allprotect Tissue Reagent to stabilize DNA, RNA and protein.
However, previously frozen tissues thaw too slowly in the reagent, preventing the reagent
from diffusing into the tissues quickly enough to prevent RNA degradation.
12. Disrupt the tissue and homogenize the lysate in Buffer RLT Plus (do not use more than
5 mg tissue) according to step 2a, 2b or 2c.
See “Disrupting and homogenizing starting material”, page 15, for more details on
disruption and homogenization.
Note: Ensure that β-ME (or DTT) is added to Buffer RLT Plus before use (see “Things to do
before starting”).
Note: If processing <2 µg tissue, 20 ng carrier RNA (5 µl of a 4 ng/µl solution) may be
added to the lysate before homogenization. Prepare the carrier RNA as described in
“Things to do before starting”.
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After storage in RNAprotect Tissue Reagent or Allprotect Reagent, tissues may become
slightly harder than fresh or thawed tissues. Disruption and homogenization using
standard methods is usually not a problem.
Note: Incomplete homogenization leads to significantly reduced RNA yields and can
cause clogging of the gDNA Eliminator and RNeasy MinElute spin columns.
Homogenization with the TissueRuptor or TissueLyser II generally results in higher RNA
yields than with other methods.
12a. Disruption and homogenization using the TissueRuptor II:
Place the tissue in a suitably sized vessel. Add 350 µl Buffer RLT Plus.
Note: Use a suitably sized vessel with sufficient extra headspace to accommodate
foaming, which may occur during homogenization.
Generally, round-bottomed tubes allow more efficient disruption and homogenization
than conical-bottomed tubes.
Place the tip of the disposable probe into the vessel and operate the TissueRuptor II at
full speed until the lysate is homogeneous (usually 30 s). Proceed to step 3.
Note: To avoid damage to the TissueRuptor II and disposable probe during operation,
make sure the tip of the probe remains submerged in the buffer.
Foaming may occur during homogenization. If this happens, let the homogenate stand at
room temperature (15–25ºC) for 2–3 min until the foam subsides before continuing with
the procedure.
12b. Disruption and homogenization using the TissueLyser II:
Place the tissues in 2 ml microcentrifuge tubes containing one stainless steel bead
(5 mm mean diameter).
If handling fresh or frozen tissue samples, keep the tubes on dry ice.
Place the tubes at room temperature. Immediately add 350 µl Buffer RLT Plus per
tube.
Place the tubes in the TissueLyser Adapter Set 2 x 24.
RNeasy Plus Micro Handbook
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35
Operate the TissueLyser II for 2 min at 20 Hz.
The time depends on the tissue being processed and can be extended until the tissue
is completely homogenized.
Rearrange the collection tubes so that the outermost tubes are innermost and the
innermost tubes are outermost. Operate the TissueLyser II for another 2 min at 20 Hz.
Rearranging the tubes allows even homogenization.
Carefully pipet the lysates into new microcentrifuge tubes (not supplied). Proceed to
step 3.
Do not reuse the stainless steel beads.
12c. Disruption using a mortar and pestle followed by homogenization using a
QIAshredder homogenizer or a needle and syringe:
Immediately place the weighed tissue in liquid nitrogen, and grind thoroughly with a
mortar and pestle.
Decant tissue powder and liquid nitrogen into an RNase-free, liquid-nitrogen–cooled,
2 ml microcentrifuge tube (not supplied). Allow the liquid nitrogen to evaporate, but
do not allow the tissue to thaw.
Add 350 µl Buffer RLT Plus.
Pipet the lysate directly into a QIAshredder spin column placed in a 2 ml collection
tube, and centrifuge for 2 min at full speed. Alternatively, pass the lysate at least
5 times through a blunt 20-gauge needle fitted to an RNase-free syringe. Proceed to
step 3.
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RNeasy Plus Micro Handbook
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13. Centrifuge the lysate for 3 min at full speed. Carefully remove the supernatant by
pipetting, and transfer it to a gDNA Eliminator spin column placed in a 2 ml collection
tube (supplied). Centrifuge for 30 s at ≥8000 x g (≥10,000 rpm). Discard the column,
and save the flow-through.
This step is important, as it removes insoluble material that could clog the gDNA
Eliminator spin column and interfere with DNA removal. In some preparations, very small
amounts of insoluble material will be present after the 3-min centrifugation, making the
pellet invisible.
Note: Make sure that no liquid remains on the column membrane after centrifugation. If
necessary, repeat the centrifugation until all liquid has passed through the membrane.
14. Add 1 volume (usually 350 µl) of 70% ethanol to the flow-through from step 3, and mix
well by pipetting. Do not centrifuge. Proceed immediately to step 5.
Note: The volume of 70% ethanol to add may be less than 350 µl if some lysate was lost
during homogenization and DNA removal.
Note: Precipitates may be visible after addition of ethanol, but this does not affect the
procedure.
Note: For maximum RNA yields from liver, use 50% ethanol instead of 70% ethanol.
15. Transfer the sample, including any precipitate that may have formed, to an RNeasy
MinElute spin column placed in a 2 ml collection tube (supplied). Close the lid gently,
and centrifuge for 15 s at ≥8000 x g (≥10,000 rpm). Discard the flowthrough.*
Optional: If recovery of protein is desired, keep the flow-through on ice and follow
steps 1–5 in Appendix E on page 60.
Reuse the collection tube in step 6.
* Flow-through contains Buffer RLT Plus or Buffer RW1 and is therefore not compatible with bleach. See page 6 for
safety information.
RNeasy Plus Micro Handbook
11/2020
37
16. Add 700 µl Buffer RW1 to the RNeasy MinElute spin column. Close the lid gently, and
centrifuge for 15 s at ≥8000 x g (≥10,000 rpm) to wash the spin column membrane.
Discard the flow-through.*
Reuse the collection tube in step 7.
Note: After centrifugation, carefully remove the RNeasy MinElute spin column from the
collection tube so that the column does not contact the flow-through. Be sure to empty the
collection tube completely.
17. Add 500 µl Buffer RPE to the RNeasy MinElute spin column. Close the lid gently, and
centrifuge for 15 s at ≥8000 x g (≥10,000 rpm) to wash the spin column membrane.
Discard the flow-through.
Reuse the collection tube in step 8.
Note: Buffer RPE is supplied as a concentrate. Ensure that ethanol is added to Buffer RPE
before use (see “Things to do before starting”).
18. Add 500 µl of 80% ethanol to the RNeasy MinElute spin column. Close the lid gently,
and centrifuge for 2 min at ≥8000 x g (≥10,000 rpm) to wash the spin column
membrane. Discard the collection tube with the flow-through.
Prepare the 80% ethanol with ethanol (96–100%) and the RNase-free water supplied
with the kit.
Note: After centrifugation, carefully remove the RNeasy MinElute spin column from the
collection tube so that the column does not contact the flow-through. Otherwise,
carryover of ethanol will occur.
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RNeasy Plus Micro Handbook
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19. Place the RNeasy MinElute spin column in a new 2 ml collection tube (supplied). Open
the lid of the spin column, and centrifuge at full speed for 5 min. Discard the collection
tube with the flow-through.
To avoid damage to their lids, place the spin columns into the centrifuge with at least one
empty position between columns. Orient the lids so that they point in a direction opposite
to the rotation of the rotor (e.g., if the rotor rotates clockwise, orient the lids
counterclockwise).
It is important to dry the spin column membrane, since residual ethanol may interfere with
downstream reactions. Centrifugation with the lids open ensures that no ethanol is
carried over during RNA elution.
20. Place the RNeasy MinElute spin column in a new 1.5 ml collection tube (supplied). Add
14 µl RNase-free water directly to the center of the spin column membrane. Close the lid
gently, and centrifuge for 1 min at full speed to elute the RNA.
As little as 10 µl RNase-free water can be used for elution if a higher RNA concentration
is required, but the yield will be reduced by approximately 20%. Do not elute with less
than 10 µl RNase-free water, as the spin column membrane will not be sufficiently
hydrated.
The dead volume of the RNeasy MinElute spin column is 2 µl: elution with 14 µl RNase-
free water results in a 12 µl eluate.
For RT-PCR and real-time RT-PCR with the purified RNA, QIAGEN offers a range of
optimized, ready-to-use kits that provide highly specific and sensitive results. For details,
visit www.qiagen.com/PCR. For whole transcriptome amplification (WTA) of limited
amounts of RNA, we recommend the QuantiTect Whole Transcriptome Kit.
RNeasy Plus Micro Handbook
11/2020
39
Protocol: Purification of Total RNA from
Microdissected Cryosections
This protocol is for the purification of total RNA from frozen, microdissected samples of animal
and human tissues. For total RNA purification from microdissected, formalin-fixed samples, we
recommend the RNeasy FFPE Kit (cat. no. 74404).
Laser-microdissected tissue specimens present a particular challenge for molecular analysis, as
nucleic acids must be purified from very small amounts of starting material. In addition, fixation
and staining steps may compromise the integrity of RNA, and it may be necessary either to
modify fixation protocols or to use cryosections from flash-frozen specimens to minimize this
problem.
A wide range of equipment and consumables for sectioning, staining and microdissection of
specimens is available from Leica (www.leica-microsystems.com) and P.A.L.M. Microlaser
Technologies (www.palm-mikrolaser.com).
Important points before starting
If using the RNeasy Plus Micro Kit for the first time, read “Important Notes” (page 11).
If preparing RNA for the first time, read Appendix A (page 49).
To minimize RNA degradation, avoid prolonged storage of unstabilized samples at room
temperature (15–25ºC). RNA in tissues is not protected before flash-freezing in liquid
nitrogen.
Tissue lysates from step 3 can be stored at –90°C to –65°C for several months. Incubate
frozen lysates at 37ºC in a water bath until completely thawed and salts are dissolved
before continuing with step 4. Avoid prolonged incubation, which may compromise RNA
integrity.
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RNeasy Plus Micro Handbook
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Buffer RLT Plus and Buffer RW1 contain a guanidine salt and are therefore not
compatible with disinfecting reagents containing bleach. See page 5 for safety
information.
Perform all steps of the procedure at room temperature (15–25ºC). During the procedure,
work quickly.
Perform all centrifugation steps at 20–25ºC in a standard microcentrifuge. Ensure that the
centrifuge does not cool below 20ºC.
Things to do before starting
β-Mercaptoethanol (β-ME) must be added to Buffer RLT Plus before use. Add 10 µl β-ME
per 1 ml Buffer RLT Plus. Dispense in a fume hood and wear appropriate protective
clothing. Buffer RLT Plus containing β-ME can be stored at room temperature (15–25ºC)
for up to 1 month. Alternatively, add 20 µl of 2 M dithiothreitol (DTT) per 1 ml Buffer RLT
Plus. The stock solution of 2 M DTT in water should be prepared fresh or frozen in single-
use aliquots. Buffer RLT Plus containing DTT can be stored at room temperature for up to
1 month.
When processing <500 cells, carrier RNA may be added to the lysate before
homogenization (see “Carrier RNA”, page 17). Before using for the first time, dissolve
the carrier RNA (310 µg) in 1 ml RNase-free water. Store this stock solution at –30°C to
–15°C, and use it to make fresh dilutions for each set of RNA preps. The concentration of
this stock solution is 310 µg/ml (i.e., 310 ng/µl). To make a working solution (4 ng/µl)
for 10 preps, add 5 µl stock solution to 34 µl Buffer RLT Plus and mix by pipetting. Add
6 µl of this diluted solution to 54 µl Buffer RLT Plus to give a working solution of 4 ng/µl.
Add 5 µl of this solution to the lysate in step 2. Do not add the carrier RNA to the lysate if
purifying RNA for use in oligo-dT–based amplification.
Buffer RPE is supplied as a concentrate. Before using for the first time, add 4 volumes of
ethanol (96–100%) as indicated on the bottle to obtain a working solution.
RNeasy Plus Micro Handbook
11/2020
41
Before using the kit for the first time, prepare 80% ethanol by mixing 24 ml ethanol
(96–100%) and 6 ml RNase-free water (supplied). The procedure also requires 70%
ethanol, which can be prepared by diluting ethanol (96–100%) with distilled water (not
supplied).
Buffer RLT Plus may form a precipitate during storage. If necessary, redissolve by
warming, and then place at room temperature.
Procedure
1. Collect the sample directly into an appropriate volume of Buffer RLT Plus (the volume
depends on the collection vessel used for microdissection, but should not be greater than
65 µl [Leica
®
instruments] or 300 µl [other instruments]).
Note: Ensure that β-ME (or DTT) is added to Buffer RLT Plus before use (see “Things to do
before starting”).
2. If necessary, transfer the sample and buffer to a larger vessel (e.g., 1.5 or 2 ml tube).
Adjust the volume to 350 µl with Buffer RLT Plus.
Note: If processing <500 cells, 20 ng carrier RNA (5 µl of a 4 ng/µl solution) may be
added to the lysate before homogenization. Prepare the carrier RNA as described in
“Things to do before starting”.
3. Vortex the sample for 30 s.
No further homogenization is necessary.
4. Transfer the sample to a gDNA Eliminator spin column placed in a 2 ml collection tube
(supplied). Centrifuge for 30 s at ≥8000 x g (≥10,000 rpm). Discard the column, and
save the flow-through.
Note: Make sure that no liquid remains on the column membrane after centrifugation. If
necessary, repeat the centrifugation until all liquid has passed through the membrane.
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RNeasy Plus Micro Handbook
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5. Add 1 volume (usually 350 µl) of 70% ethanol to the flow-through from step 4, and mix
well by pipetting. Do not centrifuge. Proceed immediately to step 6.
Note: The volume of 70% ethanol to add may be less than 350 µl if some lysate was lost
during homogenization and DNA removal.
Note: Precipitates may be visible after addition of ethanol. This does not affect the
procedure.
6. Transfer the sample, including any precipitate that may have formed, to an RNeasy
MinElute spin column placed in a 2 ml collection tube (supplied). Close the lid gently,
and centrifuge for 15 s at ≥8000 x g (≥10,000 rpm). Discard the flow-through.*
Reuse the collection tube in step 7.
7. Add 700 µl Buffer RW1 to the RNeasy MinElute spin column. Close the lid gently, and
centrifuge for 15 s at ≥8000 x g (≥10,000 rpm) to wash the spin column membrane.
Discard the flow-through.*
Reuse the collection tube in step 8.
Note: After centrifugation, carefully remove the RNeasy MinElute spin column from the
collection tube so that the column does not contact the flow-through. Be sure to empty the
collection tube completely.
8. Add 500 µl Buffer RPE to the RNeasy MinElute spin column. Close the lid gently, and
centrifuge for 15 s at ≥8000 x g (≥10,000 rpm) to wash the spin column membrane.
Discard the flow-through.
Reuse the collection tube in step 9.
Note: Buffer RPE is supplied as a concentrate. Ensure that ethanol is added to Buffer RPE
before use (see “Things to do before starting”).
* Flow-through contains Buffer RLT or Buffer RW1 and is therefore not compatible with bleach. See page 6 for safety
information.
RNeasy Plus Micro Handbook
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43
9. Add 500 µl of 80% ethanol to the RNeasy MinElute spin column. Close the lid gently,
and centrifuge for 2 min at ≥8000 x g (≥10,000 rpm) to wash the spin column
membrane. Discard the flow-through and collection tube.
Prepare the 80% ethanol with ethanol (96–100%) and the RNase-free water supplied
with the kit.
Note: After centrifugation, carefully remove the RNeasy MinElute spin column from the
collection tube so that the column does not contact the flow-through. Otherwise,
carryover of ethanol will occur.
10. Place the RNeasy MinElute spin column in a new 2 ml collection tube (supplied). Open
the lid of the spin column, and centrifuge at full speed for 5 min. Discard the collection
tube with the flow-through.
To avoid damage to their lids, place the spin columns into the centrifuge with at least one
empty position between columns. Orient the lids so that they point in a direction opposite
to the rotation of the rotor (e.g., if the rotor rotates clockwise, orient the lids
counterclockwise).
It is important to dry the spin column membrane, since residual ethanol may interfere with
downstream reactions. Centrifugation with the lids open ensures that no ethanol is
carried over during RNA elution.
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11. Place the RNeasy MinElute spin column in a new 1.5 ml collection tube (supplied). Add
14 µl RNase-free water directly to the center of the spin column membrane. Close the lid
gently, and centrifuge for 1 min at full speed to elute the RNA.
As little as 10 µl RNase-free water can be used for elution if a higher RNA concentration
is required, but the yield will be reduced by approximately 20%. Do not elute with less
than 10 µl RNase-free water, as the spin column membrane will not be sufficiently
hydrated.
The dead volume of the RNeasy MinElute spin column is 2 µl: elution with 14 µl RNase-
free water results in a 12 µl eluate.
For RT-PCR and real-time RT-PCR with the purified RNA, QIAGEN offers a range of
optimized, ready-to-use kits that provide highly specific and sensitive results. For details,
visit www.qiagen.com/PCR. For whole transcriptome amplification (WTA) of limited
amounts of RNA, we recommend the QuantiTect Whole Transcriptome Kit.
RNeasy Plus Micro Handbook
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45
Troubleshooting Guide
This troubleshooting guide may be helpful in solving any problems that may arise. The scientists
in QIAGEN Technical Services are always happy to answer any questions you may have
about either the information and protocols in this handbook or molecular biology applications
(for contact information, see back cover or visit www.qiagen.com).
Comments and suggestions
Clogged RNeasy MinElute spin column
a) Inefficient disruption
and/or
homogenization
See “Disrupting and homogenizing starting materials”
(page 15) for details on disruption and homogenization
methods.
Increase g-force and centrifugation time if necessary.
In subsequent preparations, reduce the amount of starting
material (see the individual protocols) and/or increase the
homogenization time.
b) Too much starting
material
Reduce the amount of starting material (see the individual
protocols). It is essential to use the correct amount of starting
material.
c) Centrifugation
temperature too low
The centrifugation temperature should be 20–25ºC. Some
centrifuges may cool to below 20ºC even when set at 20ºC.
This can cause formation of precipitates that can clog the spin
column. If this happens, set the centrifugation temperature to
25ºC. Warm the lysate to 37ºC before transferring it to the
gDNA Eliminator spin column.
Low RNA yield
a) Insufficient disruption
and homogenization
See “Disrupting and homogenizing starting materials”
(page 15) for details on disruption and homogenization
methods.
In subsequent preparations, reduce the amount of starting
material (see the individual protocols) and/or increase the
volume of lysis buffer and the homogenization time.
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Comments and suggestions
b) Too much starting
material
In subsequent preparations, reduce the amount of starting
material (see the individual protocols). It is essential to use the
correct amount of starting material.
c) RNA still bound to
spin column
membrane
Repeat RNA elution, but incubate the RNeasy MinElute spin
column on the benchtop for 10 min with RNase-free water
before centrifuging.
d) Ethanol carryover
After the wash with 80% ethanol, be sure to centrifuge at full
speed for 5 min to dry the RNeasy MinElute spin column
membrane.
After centrifugation, carefully remove the RNeasy MinElute
spin column from the collection tube so that the column does
not contact the flow-through. Otherwise, carryover of ethanol
will occur.
e) Incomplete removal of
cell-culture medium
(cell samples)
When processing cultured cells, ensure complete removal of
cell-culture medium after harvesting cells (see protocol,
page 21).
f) 80% ethanol not
made with RNase-free
water
The 80% ethanol used to wash the RNeasy MinElute spin
column membrane must be free of RNases. Be sure to prepare
the 80% ethanol using ethanol (96–100%) and the RNase-
free water supplied with the kit, as described in “Things to do
before starting” in each protocol.
Low or no recovery of RNA
a) RNase-free water
incorrectly dispensed
Pipet RNase-free water to the center of the RNeasy MinElute
spin column membrane to ensure that the membrane is
completely covered.
b) Ethanol carryover
After the wash with 80% ethanol, be sure to centrifuge at full
speed for 5 min to dry the RNeasy MinElute spin column
membrane.
After centrifugation, carefully remove the RNeasy MinElute
spin column from the collection tube so that the column does
not contact the flow-through. Otherwise, carryover of ethanol
will occur.
RNeasy Plus Micro Handbook
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47
Comments and suggestions
Low
A
260
/
A
280
value
Water use to dilute
RNA for A
260
/A
280
measurement
Use 10 mM Tris·Cl, pH 7.5, not RNase-free water, to dilute
the sample before measuring purity (see Appendix B,
page
Error! Bookmark not defined.
)
RNA degraded
a) Inappropriate
handling of starting
material
Ensure that tissue samples are properly stabilized and stored
in RNAprotect Tissue Reagent or Allprotect Tissue Reagent.
For frozen cell pellets or frozen tissue samples, ensure that
they were flash-frozen immediately in liquid nitrogen and
properly stored at –90°C to –65°C. Perform the RNeasy
procedure quickly, especially the first few steps.
See Appendix A (page 49) and “Handling and storing
starting material” (page 13).
b) RNase contamination
Although all RNeasy buffers have been tested and are
guaranteed RNase-free, RNases can be introduced during
use. Be certain not to introduce any RNases during the
RNeasy procedure or later handling. See Appendix A
(page 49) for general remarks on handling RNA.
Do not put RNA samples into a vacuum dryer or
microcentrifuge that has been used in DNA preparation
where RNases may have been used.
c) 80% ethanol not
made with RNase-free
water
The 80% ethanol used to wash the RNeasy MinElute spin
column membrane must be free of RNases. Be sure to prepare
the 80% ethanol using ethanol (96–100%) and the RNase-
free water supplied with the kit, as described in “Things to do
before starting” in each protocol.
Contamination of RNA with DNA affects downstream applications
a) Cell number too high
For some cell types, the efficiency of DNA binding to the
gDNA Eliminator spin column may be reduced when
processing very high cell numbers. If the eluted RNA contains
substantial DNA contamination, try processing smaller cell
numbers.
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Comments and suggestions
b) Incomplete removal of
cell-culture medium or
stabilization reagent
Be sure to remove any excess cell-culture medium or
stabilization reagent to prevent significant dilution of the lysis
buffer. The gDNA Eliminator spin column will not bind DNA
effectively if the lysis buffer is diluted.
c) Tissue has high DNA
content
For certain tissues with extremely high DNA content (e.g.,
thymus), trace amounts of DNA may pass through the gDNA
Eliminator spin column. Try using smaller samples.
RNA does not perform well in downstream experiments
a) Ethanol carryover
After the wash with 80% ethanol, be sure to centrifuge at full
speed for 5 min to dry the RNeasy MinElute spin column
membrane.
After centrifugation, carefully remove the RNeasy MinElute
spin column from the collection tube so that the column does
not contact the flow-through. Otherwise, carryover of ethanol
will occur.
b) Salt carryover during
elution
Ensure that buffers are at 20–30ºC.
Ensure that the correct buffer is used for each step of the
procedure.
When reusing collection tubes between washing steps,
remove residual flow-through from the rim by blotting on
clean paper towels.
c) Reverse transcription
with too small an
amount of RNA
When performing reverse transcription with very small
amounts of RNA, we recommend using the Sensiscript
®
RT
Kit, which is specially designed for cDNA synthesis from
<50 ng RNA. If synthesizing cDNA for use in real-time PCR,
we recommend the QuantiNova
®
Reverse Transcription Kit,
which is compatible with a wide range of RNA amounts
(10 pg to 1 µg). For ordering information, see page 62.
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49
Appendix A: General Remarks on Handling
RNA
Handling RNA
Ribonucleases (RNases) are very stable and active enzymes that generally do not require
cofactors to function. Since RNases are difficult to inactivate and even minute amounts are
sufficient to destroy RNA, do not use any plasticware or glassware without first eliminating
possible RNase contamination. Great care should be taken to avoid inadvertently introducing
RNases into the RNA sample during or after the purification procedure. To create and maintain
an RNase-free environment, the following precautions must be taken during pretreatment and
use of disposable and nondisposable vessels and solutions while working with RNA.
General handling
Proper microbiological, aseptic technique should always be used when working with RNA.
Hands and dust particles may carry bacteria and molds and are the most common sources of
RNase contamination. Always wear latex or vinyl gloves while handling reagents and RNA
samples to prevent RNase contamination from the surface of the skin or from dusty laboratory
equipment. Change gloves frequently and keep tubes closed whenever possible. Keep purified
RNA on ice when aliquots are pipetted for downstream applications. To remove RNase
contamination from bench surfaces, nondisposable plasticware and laboratory equipment
(e.g., pipets and electrophoresis tanks), use general laboratory reagents. To decontaminate
plasticware, rinse with 0.1 M NaOH, 1 mM EDTA,* followed by RNase-free water (see
”Solutions”, page 50), or rinse with chloroform* if the plasticware is chloroform-resistant. To
decontaminate electrophoresis tanks, clean with detergent (e.g., 0.5% SDS),* rinse with
RNase-free water, then rinse with ethanol (if the tanks are ethanol resistant) and allow to dry.
* When working with chemicals, always wear a suitable lab coat, disposable gloves and protective goggles. For more
information, consult the appropriate safety data sheets (SDSs), available from the product supplier.
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Disposable plasticware
The use of sterile, disposable polypropylene tubes is recommended throughout the procedure.
These tubes are generally RNase-free and do not require pretreatment to inactivate RNases.*
When working with chemicals, always wear a suitable lab coat, disposable gloves and
protective goggles. For more information, consult the appropriate safety data sheets (SDSs),
available from the product supplier. Glassware should be treated before use to ensure that it
is RNase-free. Glassware used for RNA work should be cleaned with a detergent,* thoroughly
rinsed and oven baked at 240ºC for at least 4 hours (overnight, if more convenient) before
use. Autoclaving alone will not fully inactivate many RNases. Alternatively, glassware can be
treated with diethyl pyrocarbonate (DEPC)*, as described in “Solutions” below.
Solutions
Solutions (water and other solutions) should be treated with 0.1% DEPC. DEPC is a strong, but
not absolute, inhibitor of RNases. It is commonly used at a concentration of 0.1% to inactivate
RNases on glass or plasticware or to create RNase-free solutions and water. DEPC inactivates
RNases by covalent modification. Add 0.1 ml DEPC to 100 ml of the solution to be treated
and shake vigorously to bring the DEPC into solution. Let the solution incubate for 12 hours at
37ºC. Autoclave for 15 minutes to remove any trace of DEPC. DEPC will react with primary
amines and cannot be used directly to treat Tris* buffers. DEPC is highly unstable in the
presence of Tris buffers and decomposes rapidly into ethanol and CO
2
. When preparing Tris
buffers, treat water with DEPC first, and then dissolve Tris to make the appropriate buffer.
Trace amounts of DEPC will modify purine residues in RNA by carbethoxylation.
Carbethoxylated RNA is translated with very low efficiency in cell-free systems. However, its
ability to form DNA:RNA or RNA:RNA hybrids is not seriously affected unless a large fraction
of the purine residues has been modified. Residual DEPC must always be eliminated from
solutions or vessels by autoclaving or heating to 100ºC for 15 minutes.
* When working with chemicals, always wear a suitable lab coat, disposable gloves and protective goggles. For more
information, consult the appropriate safety data sheets (SDSs), available from the product supplier.
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51
Note: RNeasy buffers are guaranteed RNase-free without using DEPC treatment and are
therefore free of any DEPC contamination.
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Appendix B: Storage, Quantification and
Determination of Quality of RNA
Storage of RNA
Purified RNA may be stored at –70ºC to –15ºC in RNase-free water. Under these conditions,
no degradation of RNA is detectable after 1 year.
Quantification of RNA
The concentration of RNA should be determined by measuring the absorbance at 260 nm
(A
260
) in a spectrophotometer (see “Spectrophotometric quantification of RNA” below). For
small amounts of RNA, however, it may be difficult to determine amounts photometrically.
Small amounts of RNA can be quantified using quantitative RT-PCR or fluorometric
quantification.
Spectrophotometric quantification of RNA
Using the QIAxpert UV/VIS Spectrophotometer for microvolume analysis
To determine the concentration of your RNA sample purified with RNeasy QIAGEN kit, use
the corresponding RNeasy App on the QIAxpert. For more information, see the QIAxpert
product page (www.qiagen.com/qiaxpert-system).
Using a standard spectrophotometer
To ensure significance, A
260
readings should be greater than 0.15. An absorbance of 1 unit
at 260 nm corresponds to 44 µg of RNA per ml (A
260
= 1 4 µg/ml). This relation is valid
only for measurements at a neutral pH. Therefore, if it is necessary to dilute the RNA sample,
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53
this should be done in a buffer with neutral pH.* As discussed below (see “Purity of RNA”,
page 53), the ratio between the absorbance values at 260 and 280 nm gives an estimate of
RNA purity. When measuring RNA samples, be certain that cuvettes are RNase-free, especially
if the RNA is to be recovered after spectrophotometry. This can be accomplished by washing
cuvettes with 0.1 M NaOH, 1 mM EDTA,* followed by washing with RNase-free water (see
“Solutions”, page 50). Use the buffer in which the RNA is diluted to zero the
spectrophotometer. An example of the calculation involved in RNA quantification is shown
below:
Volume of RNA sample = 100 µl
Dilution = 10 µl of RNA sample + 490 µl of 10 mM Tris·Cl,* pH 7.0
(1/50 dilution)
Measure absorbance of diluted sample in a 1 ml cuvette (RNase-free)
A
260
= 0.2
Concentration of RNA sample = 44 µg/ml x A
260
x dilution factor
= 44 µg/ml x 0.2 x 50
= 440 µg/ml
Total amount = concentration x volume in milliliters
= 440 µg/ml x 0.1 ml
= 44 µg of RNA
Purity of RNA
The assessment of RNA purity will be performed routinely, when using the QIAxpert with the
corresponding RNeasy App. See the QIAxpert user manual for more information
(www.qiagen.com/qiaxpert-system/user manual)
* When working with chemicals, always wear a suitable lab coat, disposable gloves and protective goggles. For more
information, consult the appropriate safety data sheets (SDSs), available from the product supplier.
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For standard photometric measurements, the ratio of the readings at 260 nm and 280 nm
(A
260
/A
280
) provides an estimate of the purity of RNA with respect to contaminants, such as
protein, that absorb in the UV spectrum. However, the A
260
/A
280
ratio is influenced
considerably by pH. Since water is not buffered, the pH and the resulting A
260
/A
280
ratio can
vary greatly when using pure water. Lower pH results in a lower A
260
/A
280
ratio and reduced
sensitivity to protein contamination.* For accurate values, we recommend measuring
absorbance in 10 mM Tris·Cl, pH 7.5. Pure RNA has an A
260
/A
280
ratio of 1.9–2.1
in 10 mM
Tris·Cl, pH 7.5. Always be sure to calibrate the spectrophotometer with the same solution used
for dilution. For determination of RNA concentration, however, we recommend dilution of the
sample in a buffer with neutral pH since the relationship between absorbance and
concentration (A
260
reading of 1 = 44 µg/ml RNA) is based on an extinction coefficient
calculated for RNA at neutral pH (see “Spectrophotometric quantification of RNA”, page 52).
DNA contamination
No currently available purification method can guarantee that RNA is completely free of DNA,
even when it is not visible on an agarose gel. RNeasy Kits will, however, remove the vast
majority of cellular DNA. gDNA Eliminator Solution helps to further reduce genomic DNA
contamination; however, trace amounts of genomic DNA may still remain, depending on the
amount and nature of the sample. For analysis of very low abundance targets, any interference
by residual DNA contamination can be detected by performing real-time RT-PCR control
experiments in which no reverse transcriptase is added prior to the PCR step.
To prevent any interference by DNA in real-time RT-PCR applications, such as with Applied
Biosystems
®
and Rotor-Gene
®
instruments, we recommend designing primers that anneal at
intron splice junctions so that genomic DNA will not be amplified. QuantiTect Primer Assays
from QIAGEN are designed for SYBR
®
Green-based real-time RT-PCR analysis of RNA
sequences (without detection of genomic DNA) where possible (see
www.qiagen.com/GeneGlobe). For real-time RT-PCR assays where amplification of genomic
* Wilfinger, W.W., Mackey, M., and Chomczynski, P. (1997) Effect of pH and ionic strength on the
spectrophotometric assessment of nucleic acid purity. BioTechniques 22, 474.
Values up to 2.3 are routinely obtained for pure RNA (in 10 mM Tris·Cl, pH 7.5) with some spectrophotometers.
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55
DNA cannot be avoided, we recommend using the QuantiTect Reverse Transcription Kit for
reverse transcription. The kit integrates fast cDNA synthesis with rapid removal of genomic
DNA contamination (see ordering information, page 62).
Integrity of RNA
The integrity and size distribution of total RNA purified with RNeasy Plus Universal Kits can be
checked by denaturing agarose gel electrophoresis and ethidium bromide staining* or by
using the QIAxcel system or Agilent
®
2100 Bioanalyzer. Ribosomal RNAs should appear as
sharp bands or peaks. The apparent ratio of 28S rRNA to 18S rRNA should be approximately
2:1. If the ribosomal bands or peaks of a specific sample are not sharp, but appear as a
smear towards smaller sized RNAs, it is likely that the sample suffered major degradation
either before or during RNA purification. As a useful measure of RNA integrity, the QIAxcel
®
Advanced system and the Agilent 2100 Bioanalyzer provide an RNA integrity score (RIS) and
an RNA integrity number (RIN), respectively. Ideally, the value should be close to 10, but in
many cases (particularly with tissue samples), RNA quality is greatly influenced by how well
the original sample was preserved.
* When working with chemicals, always wear a suitable lab coat, disposable gloves and protective goggles. For more
information, consult the appropriate safety data sheets (SDSs), available from the product supplier.
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Appendix C: RNA Cleanup and Concentration
The RNeasy Plus Micro Kit can be used to clean up crude RNA samples. For RNA samples
that were purified by phenol/chloroform extraction and will be analyzed using sensitive
methods, such as real-time RT-PCR, cleanup of the RNA with the RNeasy Plus Micro Kit, ensures
effective removal of contaminants, such as genomic DNA and phenol, which can interfere with
transcript quantification. The kit also has the additional benefit of concentrating RNA samples,
enabling the use of more RNA template per reaction and/or smaller reaction volumes.
Procedure
1. Add 350 µl Buffer RLT Plus to a maximum of 50 µl of crude RNA, or dissolve a crude
RNA pellet in 350 µl Buffer RLT Plus. Mix well by pipetting.
2. Proceed to step 4 of the protocol for animal and human cells on page 21.
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57
Appendix D: Purification of Total RNA
Containing Small RNAs from Cells
The following procedure allows the purification of total RNA containing small RNAs, such as
miRNA from animal and human cells.
Reagents to be supplied by user
Ethanol (100%)*
Important points before starting
Perform all steps of the procedure at room temperature (15–25ºC). During the procedure,
work quickly.
Perform all centrifugation steps at 20–25ºC in a standard microcentrifuge. Ensure that the
centrifuge does not cool below 20ºC.
Things to do before starting
Buffer RPE is supplied as a concentrate. Before using for the first time, add 4 volumes of
ethanol (96–100%) as indicated on the bottle to obtain a working solution.
Procedure
Carry out the protocol starting on page 21 up to and including step 4. Instead of performing
steps 5–11 (purification of total RNA >200 nucleotides), follow steps 1–6 below (purification
of total RNA containing small RNAs).
* When working with chemicals, always wear a suitable lab coat, disposable gloves and protective goggles. For more
information, consult the appropriate safety data sheets (SDSs), available from the product supplier.
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1. Add 1.5 volumes (usually 525 µl) of 100% ethanol to the flow-through from the gDNA
Eliminator spin column, and mix well by pipetting. Do not centrifuge. Proceed
immediately to step D2.
Note: The volume of 100% ethanol to add may be less than 525 µl if some lysate was
lost during homogenization and DNA removal.
Note: Precipitates may be visible after addition of ethanol, but this does not affect the
procedure.
2. Transfer 700 µl of the sample, including any precipitate that may have formed, to an
RNeasy MinElute spin column placed in a 2 ml collection tube (supplied). Close the lid
gently, and centrifuge for 15 s at ≥8000 x g (≥10,000 rpm). Discard the flow-through.*
Repeat step D2 until the whole sample has passed through the membrane. Discard the
flow-through each time.
Reuse the collection tube in step D3.
3. Add 500 µl Buffer RPE to the RNeasy MinElute spin column. Close the lid gently, and
centrifuge for 15 s at ≥8000 x g (≥10,000 rpm) to wash the spin column membrane.
Discard the flow-through.
Reuse the collection tube in step D4.
Note: Buffer RPE is supplied as a concentrate. Ensure that ethanol is added to Buffer RPE
before use (see “Things to do before starting”).
* Flow-through contains Buffer RLT Plus and is therefore not compatible with bleach. See page 6 for safety information.
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59
4. Add 500 µl Buffer RPE to the RNeasy MinElute spin column. Close the lid gently, and
centrifuge for 2 min at ≥8000 x g (≥10,000 rpm) to wash the spin column membrane.
Discard the collection tube with the flow-through.
Note: After centrifugation, carefully remove the RNeasy MinElute spin column from the
collection tube so that the column does not contact the flow-through. Otherwise,
carryover of ethanol will occur.
5. Place the RNeasy MinElute spin column in a new 2 ml collection tube (supplied). Open
the lid of the spin column, and centrifuge at full speed for 5 min. Discard the collection
tube with the flow-through.
To avoid damage to their lids, place the spin columns into the centrifuge with at least one
empty position between columns. Orient the lids so that they point in a direction opposite
to the rotation of the rotor (e.g., if the rotor rotates clockwise, orient the lids
counterclockwise).
It is important to dry the spin column membrane, since residual ethanol may interfere with
downstream reactions. Centrifugation with the lids open ensures that no ethanol is
carried over during RNA elution.
6. Place the RNeasy MinElute spin column in a new 1.5 ml collection tube (supplied). Add
14 µl RNase-free water directly to the center of the spin column membrane. Close the lid
gently, and centrifuge for 1 min at full speed to elute the RNA (total RNA containing
small RNAs).
As little as 10 µl RNase-free water can be used for elution if a higher RNA concentration
is required, but the yield will be reduced by approximately 20%. Do not elute with less
than 10 µl RNase-free water, as the spin column membrane will not be sufficiently
hydrated.
The dead volume of the RNeasy MinElute spin column is 2 µl: elution with 14 µl RNase-
free water results in a 12 µl eluate.
For real-time RT-PCR with the purified RNA, QIAGEN offers the miScript System, which
allows detection of hundreds of miRNAs from a single cDNA synthesis reaction
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Appendix E: Acetone Precipitation of Protein
from Lysates
The following procedure describes how to recover denatured protein by acetone precipitation
from lysates of cells and easy-to-lyse tissues.
Reagents to be supplied by user
Ice
Acetone*
Optional: Ethanol*
Buffer* for downstream application (e.g., loading buffer for SDS-PAGE gel)
Important points before starting
Do not use trichloroacetic acid (TCA) to precipitate protein from Buffer RLT Plus lysates.
This buffer contains guanidine thiocyanate, which can form highly reactive compounds
when combined with acidic solutions.
Procedure
Bind total RNA to the RNeasy MinElute spin column as described in the cell protocol (from
page 21, steps 1–6) or the tissue protocol (from page 30, steps 1–5). Then follow steps 1–5
below to precipitate protein from the flow-through.
7. Add 4 volumes of ice-cold acetone to the flow-through from the RNeasy MinElute spin
column.
8. Incubate for 30 min on ice or at –30°C to –15°C.
* When working with chemicals, always wear a suitable lab coat, disposable gloves and protective goggles. For more
information, consult the appropriate safety data sheets (SDSs), available from the product supplier.
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61
9. Centrifuge for 10 min at full speed in a benchtop centrifuge. Discard the supernatant and
air-dry the pellet.*
10. Optional: Wash the pellet with 100 µl ice-cold ethanol and air-dry.
Do not overdry the pellet as this may make resuspension more difficult.
11. Resuspend the pellet in the buffer for your downstream application.
Sodium dodecyl sulfate (SDS) causes guanidine salts to precipitate. In case the pellet
contains traces of guanidine thiocyanate, load the sample onto an SDS-PAGE gel
immediately after heating for 7 minutes at 95ºC.
* Supernatant contains guanidine thiocyanate and is therefore not compatible with bleach. See page 6 for safety
information.
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Ordering Information
Product Contents Cat. no.
RNeasy Plus Micro Kit (50)
50 RNeasy MinElute Spin Columns, 50 gDNA
Eliminator Mini Spin Columns, Collection
Tubes, Carrier RNA, RNase-Free Reagents
and Buffers
74034
RNeasy Plus Mini Kit (50)*
50 RNeasy Mini Spin Columns, 50 gDNA
Eliminator Mini Spin Columns, Collection
Tubes, RNase-Free Reagents and Buffers
74134
Accessories
RNAprotect Cell Reagent
(250 ml)
250 ml RNAprotect Cell Reagent 76526
RNAprotect Tissue Reagent
(50 ml)
50 ml RNAprotect Tissue Reagent for
stabilization of RNA in 25 x 200 mg tissue
samples
76104
RNAprotect Tissue Reagent
(250 ml)
250 ml RNAprotect Tissue Reagent for
stabilization of RNA in 125 x 200 mg tissue
samples
76106
RNAprotect Tissue Tubes
(50 x 1.5 ml)
For stabilization of RNA in 50 x 50 mg tissue
samples: 50 screw-top tubes containing 1.5
ml RNAprotect Tissue Reagent each
76154
RNAprotect Tissue Tubes
(20 x 5 ml)
For stabilization of RNA in 20 x 500 mg
tissue samples: 20 screw-top tubes containing
5 ml RNAprotect Tissue Reagent each
76163
Allprotect Tissue Reagent
(100 ml)
For stabilization of DNA/RNA/protein in
50 x 200 mg tissue samples: 100 ml
Allprotect Tissue Reagent, Allprotect Reagent
Pump
76405
Collection Tubes (2 ml) 1000 x 2 ml Collection Tubes 19201
QIAshredder (50) 50 disposable cell-lysate homogenizers 79654
QIAshredder (250) 250 disposable cell-lysate homogenizers 79656
RNeasy Plus Micro Handbook
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63
Product Contents Cat. no.
TissueRuptor II
Handheld rotor–stator homogenizer,
5 TissueRuptor Disposable Probes
Varies
TissueRuptor Disposable
Probes (25)
25 nonsterile plastic disposable probes for
use with the TissueRuptor II
990890
TissueLyser II Universal laboratory mixer-mill disruptor Varies
TissueLyser Adapter Set
2 x 24
2 sets of Adapter Plates and 2 racks for use
with 2 ml microcentrifuge tubes on the
TissueLyser II
69982
Stainless Steel Beads,
5 mm (200)
Stainless Steel Beads, suitable for use with the
TissueLyser system
69989
TissueLyser Single-Bead
Dispenser, 5 mm
For dispensing individual beads (5 mm
diameter)
69965
QIAcube Connect — for fully automated nucleic acid extraction with
QIAGEN spin-column kits
QIAcube Connect
Instrument, connectivity package, 1-year
warranty on parts and labor
Inquire
Starter Pack, QIAcube
Filter-tips, 200 µl (1024), 1000 µl filter-tips
(1024), 30 ml reagent bottles (12), rotor
adapters (240), elution tubes (240), rotor
adapter holder
990395
Related products
AllPrep
®
DNA/RNA Micro Kit — for simultaneous purification of DNA and
RNA from the same small cell or tissue sample
AllPrep DNA/RNA Micro
Kit (50)
50 AllPrep DNA Mini Spin Columns,
50 RNeasy MinElute Spin Columns, Collection
Tubes, RNase-Free Reagents and Buffers
80284
RNeasy FFPE Kit — for purification of high yields of usable RNA from FFPE
tissue sections
RNeasy FFPE Kit (50)
50 RNeasy MinElute Spin Columns, 50 gDNA
Eliminator Mini Spin Columns, Collection
Tubes, RNase-Free Reagents and Buffers
74404
64
RNeasy Plus Micro Handbook
11/2020
Product Contents Cat. no.
RNeasy MinElute Cleanup Kit — for RNA cleanup and concentration with
small elution volumes
RNeasy MinElute Cleanup
Kit (50)
50 RNeasy MinElute Spin Columns, Collection
Tubes, RNase-Free Reagents and Buffers
74204
QuantiTect Whole Transcriptome Kit — for unlimited real-time PCR analysis
from precious RNA samples
QuantiTect Whole
Transcriptome Kit (25)
§
For 25 x 50 µl whole-transcriptome-
amplification reactions: T-Script Enzyme and
Buffer, Ligation Enzymes, Reagent and Buffer,
and REPLI-g
®
DNA Polymerase and Buffer
207043
Sensiscript RT Kit — for reverse transcription using less than 50 ng RNA per
reaction
Sensiscript RT Kit (50)
§
For 50 x 20 µl reverse-transcription reactions:
Sensiscript Reverse Transcriptase, 10x Buffer
RT, dNTP Mix, RNase-Free Water
205211
QuantiNova Reverse Transcription Kit for fast cDNA synthesis and
reproducible real-time two-step RT-PCR
QuantiNova Rev.
Transcription Kit (10)
§
For 10 x 20 µl reactions: 20 µl 8x gDNA
Removal Mix, 10 µl Reverse Transcription
Enzyme, 40 µl Reverse Transcription Mix
(containing RT primers), 20 µl Internal Control
RNA, 1.9 ml RNase-Free Water
205410
QuantiNova
®
SYBR
®
Green PCR Kit — or unparalleled results using SYBR
Green-based qPCR
QuantiNova SYBR
®
Green
PCR Kit (2500)
For 2500 x 20 µl reactions: 15 x 1.7 ml
2x QuantiNova SYBR Green PCR Master Mix,
5 x 500 µl QuantiNova Yellow Template
Dilution Buffer, 5 X 1 ml QN ROX Reference
Dye, 5 x 1.9 ml Water
208056
QuantiNova SYBR
®
Green RT-PCR Kit — for one-step qRT-PCR using SYBR
®
Green I for gene expression analysis
RNeasy Plus Micro Handbook
11/2020
65
Product Contents Cat. no.
QuantiNova
®
SYBR Green
RT-PCR Kit (500)
For 500 x 20 µl reactions: 3 x 1.7 ml
QuantiNova SYBR Green RT-PCR Master Mix,
100 µl QuantiNova SYBR Green RT Mix, 100
µl Internal Control RNA, 500 µl Yellow
Template Dilution Buffer, 1 ml ROX Reference
Dye, 2 x 1.9 µl RNase-Free Water
208154
QuantiNova Probe PCR Kits — for highly sensitive, specific, and ultrafast,
probe-based real-time PCR
QuantiNova Probe PCR Kit
(500)
For 500 x 20 µl reactions: 3 x 1.7 ml 2x
QuantiNova Probe PCR Master Mix, 1 ml QN
ROX Reference Dye, 500 µl QuantiNova
Yellow Template Dilution Buffer, 1.9 ml Water
208254
QuantiNova Probe PCR Kits — for highly sensitive, specific, and ultrafast,
probe-based real-time PCRs
QuantiNova Probe RT-PCR
Kit (500)
For 500 x 20 µl reactions: 3 x 1.7 ml
QuantiNova Probe RT-PCR Master Mix,
100 µl QuantiNova Probe RT Mix, 100 µl
Internal Control RNA, 500 µl Yellow Template
Dilution Buffer, 1 ml ROX Reference Dye, 2 x
1.9 µl RNase-Free Water
208354
QuantiNova Probe PCR Kit
(500)
For 500 x 20 µl reactions: 3 x 1.7 ml 2x
QuantiNova Probe PCR Master Mix, 1 ml QN
ROX Reference Dye, 500 µl QuantiNova
Yellow Template Dilution Buffer, 1.9 ml Water
208354
* For total RNA purification from up to 1 x 10
7
cells or 30 mg tissue.
Visit www.qiagen.com/automation to find out more about the TissueRuptor II and TissueLyser II and to order.
All QIAcube Connect instruments are provided with a region-specific connectivity package, including tablet and
equipment necessary to connect to the local network. Further, QIAGEN offers comprehensive instrument service
products, including service agreements, installation, introductory training and preventive subscription. Contact your
local sales representative to learn about your options.
§
Other kit sizes available; please inquire.
For all instruments from Applied Biosystems except the Applied Biosystems 7500.
**
For the Applied Biosystems 7500 and instruments from Bio-Rad/MJ Research, Cepheid, Corbett Research,
Eppendorf, Roche and Stratagene.
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For up-to-date licensing information and product-specific disclaimers, see the respective
QIAGEN kit handbook or user manual. QIAGEN kit handbooks and user manuals are
available at www.qiagen.com or can be requested from QIAGEN Technical Services or your
local distributor.
Document Revision History
Date Changes
January 2020 Updated text, ordering information and intended use for QIAcube Connect.
November 2020 Updated branding of RNA protection products.
RNeasy Plus Micro Handbook
11/2020
67
Trademarks: QIAGEN
®
, Sample to Insight
®
, QIAcube
®
, QIAxcel
®
, AllPrep
®
, Allprotect
®
, GeneGlobe
®
, MinElute
®
, QuantiFast
®
, QuantiNova
®
, QuantiTect
®
, REPLI-g
®
,
RNAprotect
®
, RNeasy
®
, Rotor-Gene
®
, Sensiscript
®
(QIAGEN Group); Agilent
®
(Agilent Technologies, Inc.); Applied Biosystems
®
(Applera Corporation or its
subsidiaries); FACS
®
(Becton, Dickinson and Company); Leica
®
(Leica Microsystems GmbH); SYBR
®
(Molecular Probes, Inc.). Registered names, trademarks, etc. used
in this document, even when not specifically marked as such, are not to be considered unprotected by law.
HB-1950-003 © 2020 QIAGEN, all rights reserved.
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Ordering www.qiagen.com/shop | Technical Support support.qiagen.com | Website www.qiagen.com
HB
-
1950
-
00
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