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Optimize your experiments to get the best results. We’ve compiled a detailed knowledgebase of the top tips and tricks to meet your research needs.
View the relevant questions below:
RNAlater® Stabilization Solution is an aqueous tissue storage reagent that protects cellular RNA in intact, unfrozen tissue samples. RNAlater® Stabilization Solution eliminates the need to immediately process your tissue samples or to freeze them in liquid nitrogen for later processing. Read more about RNAlater® Stabilization Solution here.
RNAlater® Stabilization Solution has been tested on a variety of mammalian tissues, plants, E. coli, Xenopus, fish, and Drosophila. It has been successfully used with all of our Ambion® RNA isolation kits (see figure below) including RNAqueous® Total RNA Isolation Kits, the ToTALLY RNA™ Total RNA Isolation Kit, RNAwiz™ Reagent, and Poly(A)Purist™ Kits, as well as Molecular Research Center's TRI Reagent® products. Other commercial RNA isolation kits and standard RNA isolation protocols are also compatible with RNAlater® Stabilization Solution.
Compatibility of various RNA isolation methods with RNAlater® Stabilization Solution. Freshly dissected whole mouse liver and heart were placed in RNAlater® Stabilization Solution and stored at 4°C for 3 days. RNA was isolated from equal mass amounts of each tissue using the Ambion® ToTALLY RNA™ Total RNA Isolation Kit, RNAwiz™ Reagent, or Poly(A)Purist™ Kits.
Trim the tissue to be less than 0.5 cm in at least one dimension and simply submerge it in 5 volumes of RNAlater® Stabilization Solution (e.g., a 0.5 g sample requires about 2.5 mL of RNAlater® Stabilization Solution). Small organs such as rat kidney, liver, and spleen can be stored whole in RNAlater® Stabilization Solution. Resuspend pelleted cells in a small amount of PBS before adding 5–10 volumes of RNAlater® Stabilization Solution. You can store samples at 4°C for one month, at 25°C for one week, or at –20°C indefinitely. You can archive tissues treated with RNAlater® Stabilization Solution at –20°C.
For RNA isolation, simply remove the tissue from RNAlater® Stabilization Solution and treat it as though it was just harvested. Most tissues can be homogenized directly in lysis buffer, although harder tissues such as bone may require freezing in liquid nitrogen and grinding.
For your tissue samples, we recommend removing the tissue treated with RNAlater® Stabilization Solution from the excess RNAlater® solution after incubation overnight at 4°C, blotting the tissue on a sterile Kimwipe® wiper, and proceeding to lysis.
For your cell samples, pellet the cells, then pour off the excess RNAlater® supernatant. If possible, aspirate the RNAlater® Stabilization Solution from the cell pellet and proceed to lysis. Cells are generally less fragile after being stored in RNAlater® Stabilization Solution and can be centrifuged at higher speeds without causing cell lysis (5,000 x g).
Yes, DNA can be isolated from samples stored in RNAlater® Stabilization Solution. Please view the protocol here. Proteins will be preserved in RNAlater® Stabilization Solution; however, the solution will denature the proteins. Therefore, the protein obtained from samples stored in it will still be suitable for applications such as western blotting or 2D gel electrophoresis, but not for applications that require native protein.
RNA was evaluated after storage for over 2 years, indicating no systematic bias introduced by storage in RNAlater® Stabilization Solution. For more information, visit our webpage.
While we have not tested this in house, these references suggest that the virus remains active after treatment with RNAlater® Stabilization Solution:
RNAlater® Stabilization Solution is bacteriostatic. Although bacteria does not grow in RNAlater® solution, the cells remain intact. E. coli cells stored in RNAlater® Stabilization Solution for 1 month at 4°C are intact and yield undegraded RNA.
Yes, RNAlater® Stabilization Solution has been used with Staphylococcus epidermidis isolates. Here’s a reference describing how researchers used the solution with gram-positive bacteria:
Handke LD, Conlon KM, Slater SR et al. (2004) Genetic and phenotypic analysis of biofilm phenotypic variation in multiple Staphylococcus epidermidis isolates. J Med Microbiol 53(Pt5):367–344.
No, the tissue in RNAlater® Stabilization Solution must be stored at 4°C overnight.
Yes, you should be able to sort cells by fluorescence-activated cell sorting (FACS) after treatment with RNAlater® Stabilization Solution. If you run into problems due to the viscosity of RNAlater® Stabilization Solution, you may need to dilute it with cold nuclease-free water. This will not affect the protection of the RNA. Samples should be processed quickly and as cold as possible. Read more about this procedure and view references here. You should also be able to perform mass spectrophotometry on samples treated with RNAlater® Stabilization Solution. Please note that salt can form adducts on the protein at the desorption/ionization step. To avoid this problem, dialyze the sample to get rid of all salt.
RNA stored in RNAlater® Stabilization Solution is stable for 1 day at 37°C, 1 week at 25°C, 1 month at 4°C, or long-term at –20°C.
While we have not tested this in-house, there is evidence that it is possible to use tissues preserved in RNAlater® Stabilization Solution and then perform laser capture microdissection. Please see the reference below:
Thelen P, Burfeind P, Grzmil M et al. (2004) cDNA microarray analysis with amplified RNA after isolation of intact cellular RNA from neoplastic and non-neoplastic prostate tissue separated by laser microdissections. Int J Oncol 24(5):1085–1092.
We do not recommend this, as RNAlater® Stabilization Solution is already at a 1X concentration.
RNAlater®-ICE Frozen Tissue Transition Solution can be used to submerge a frozen sample, then thaw it overnight at –20°C or colder. Once thawed, tissues can then be processed like fresh tissues using standard RNA isolation procedures.
Nuclease | Source | Cleavage specificity | Required cofactors | Comments |
RNase A | Bovine | 3’ of single-stranded C's and U's | None | Inactivated by 0.1% SDS |
RNase I | E. coli (recombinant) | 3’ of single-stranded NTPs of RNA | None | Responsible for 98% of the EDTA-resistant RNase activity in E. coli extracts |
RNase T1 | Aspergillus oryzae (recombinant) | 3’ end of single-stranded G's | None | Specificity for G is 10^6 times greater than A |
RNase V1 | Cobra venom | dsRNA | Na+ (100 mM); Mg2+ (0.3 mM) | Cleaves ssRNA at 10% of the rate of dsRNA |
RNase H | E. coli (recombinant) | RNA of RNA:DNA hybrids to give 5’-phosphate terminated oligoribotides | Mg2+ (2–4 mM) | EDTA abolishes activity, but enzyme can still bind RNA:DNA hybrids. RNase H will not degrade DNA or unhybridized RNA |
Total RNA can be digested using RNAse A or RNase T1. A mix of both can be used in ribonuclease protection assays.
Magnesium and calcium are required cofactors for DNase I. DNase I does digest ssDNA. To learn more about DNase I, click here.
DNase can be removed by the following methods: acid phenol:choloform extraction, lithium chloride precipitation, EDTA, and heat inactivation, or using our MegaClear™ Transcription Clean-Up Kit (Cat. No. AM1908).
Alternatively, our Ambion® TURBO DNA-free™ Kit (Cat. No. AM1907) is supplied with a DNase inactivation reagent that can be used to remove the DNase, as well as divalent cations such as magnesium and calcium, which can catalyze RNA degradation when RNA is heated with the sample.
Yes, while a single DNase treatment is typically sufficient for a vast majority of DNA removal needs, a second treatment option is available. Please see the protocol here.
Yes, please visit this website for our FirstChoice® total RNA isolated from human tissues, as well as from E. coli and human cell lines.
The three salts that can be used are:
RNA and DNA absorb at 260 nm while protein absorbs at 280 nm. The A260/A280 absorbance ratio can be used to indicate the purity of the sample. For RNA, the A260/A280 ratio should be approximately 2.0. If the ratio is lower, this indicates protein or phenol contamination of the sample.
The A260/A230 ratio is a measure for pure nucleic acids, with an expected range between 2.0 and 2.2. If the ratio is much lower than this, it indicates the presence of contaminants in the sample (typically phenol, guanidine, ethanol, or glycerol used for precipitation).
The 28S and 18S bands are indicative of intact RNA. On a gel, the 28S and 18S bands should be present in an approximately 2:1 ratio.
UV spectroscopy is the traditional method for assessing RNA concentration and purity. The Agilent® 2100 Bioanalyer® instrument combines the use of microfluidics, capillary electrophoresis, and a fluorescent dye that binds to nucleic acid to evaluate both RNA concentration and integrity. Read more about both methods here.
For bacterial samples, you could use our TRIzol® Max™ Bacterial RNA Isolation Kit (Cat. No. 16096040), that contains an extra reagent during homogenization to help with lysis of the bacterial cell walls. You could also use our PureLink® RNA Mini Kit (Cat. No. 12183018A), for which you would need to prepare a lyosyme solution to lyse the cell wall.
Yes, you can use TRIzol® Reagent or the mirVana™ PARIS™ RNA and Native Protein Purification Kit.
Please visit our website for tips for working with blood samples.
No. Phasemaker tubes are only validated for RNA extraction.
Phasemaker Tubes work exclusively with TRIzol Reagent (and TRIzol LS Reagent ). As other similar reagents may have different density, Phasemaker Tubes may not work properly.
Phasemaker Tubes work on the principle of density gradient centrifugation. Phasemaker Tubes contain a thick liquid polymer that is heavier than the aqueous phase of the TRIzol Reagent mix, but lighter than the organic phase, so after centrifugation, the polymer positions itself between these two layers and forms an exclusive physical barrier. It separates and completely isolates the upper aqueous phase from the organic phase underneath, making it very easy to aspirate the upper phase containing the RNA.
Yes you can. As RNAlater incorporates salts into the sample, the salt content can increase the density of the sample mix, so we recommend adding RNAse-free water (50-100 µL) to the sample mix.
The polymer in Phasemaker Tubes is inert and heat-stable, and does not affect standard downstream applications performed after RNA extraction.
The absorbance of nucleic acids is dependent upon the ionic strength and pH of the medium. Please see the range of absorbance values below based on the diluents used.
Diluent | A260 | A280 | A260/A280 | RNA (µg/mL) |
Cytoplasmic RNA dissolved in distilled water | 0.381 | 0.223 | 1.711 | 15.24 |
Cytoplasmic RNA dissolved in TE buffer | 0.335 | 0.145 | 2.310 | 13.4 |
RNA isolated by TRIzol® Reagent and dissolved in distilled water | 0.585 | 0.328 | 1.785 | 23.4 |
RNA isolated by TRIzol® Reagent and dissolved in TE buffer | 0.544 | 0.247 | 2.206 | 21.76 |
Although a high A260/A280 ratio may not indicate an extremely pure preparation of nucleic acid, a low A260/A280 ratio (1.7 for RNA) does indicate that the preparation is contaminated and may not be suitable for some applications.
You can homogenize your samples using a glass, Teflon®, or power homogenizer (Polytron® or Tekmar’s Tissumizer® homogenizer). You do not need to homogenize cultured cells, just mix them extensively with TRIzol® Reagent. Sonication will work to lyse cells in TRIzol® Reagent. For small samples, you can try using a Dounce homogenizer.
There are several possible stopping points and recommended storage conditions during the extraction of RNA with TRIzol® Reagent:
Small volumes (0.5–0.8 mL) of TRIzol® Reagent have been used successfully for 102 to 105 cells, but if small volumes are used, we recommend using smaller tubes in order to have the tallest possible column of aqueous phase. The taller the column of liquid, the less likely that contamination from the interphase will occur.
Here is a protocol for isolation of RNA from small quantities of tissue (1–10 mg) or cells (100–10,000):
We recommend using straight chloroform. No isoamyl alcohol is needed (though using chloroform:isoamyl alcohol 49:1 works without problems). You can also use chloroform with 50 ppm amylene. Alternatively, BCP (1-bromo-2 chloropropane) can be used in the place of chloroform.
TRIzol® LS Reagent is designed to be used with liquid samples, such as serum or virus preparations, while TRIzol® Reagent is designed to be used with tissues or cells, including lipid-rich and difficult samples.
The PureLink® RNA Mini Kit was only validated to recover RNA > 200 nt. However, you can try the following modifications to isolate total RNA including small RNA:
For on-column digestion, PureLink® DNase (Cat. No. 12185010) can be used. Please see the protocol in the appendix of the manual on page 63.
Please visit our website for a graph showing purity measurements and RNA integrity number (RIN) comparison of the abovementioned kits.
The PureLink® RNA Mini Kit provides rapid column-based purification of total RNA, without organic lysis (phenol/chloroform). You can obtain up to 1,000 µg of purified RNA from a single extraction. The RiboPure™ RNA Purification Kits combine a phenol/guanidine thiocyanate solution with a glass-fiber filter purification method.
The column cut-off size is 200 nt. Using a RiboPure™ kit is not appropriate for miRNA recovery. For miRNA isolation, we would suggest using a mirVana™ kit, the TRIzol® Plus RNA Purification Kit, or the PureLink® RNA Micro Kit.
RNaqueous® kits are based on a rapid, filter-based RNA isolation system that does not require phenol, chloroform, or other toxic organic chemicals. The RNAqueous® Total RNA Isolation Kit is designed for sample sizes of 10–75 mg of tissue or 106 to 107 cells, whereas the RNAqueous®-Midi Total RNA Isolation Kit is designed for tissue samples of up to 0.5 g or 109 cells. The RNAqueous®-Micro Total RNA Isolation Kit is optimized for the purification of total RNA from micro-sized samples such as 10–500,000 cultured cells, as few as 10 microdissected cells, or up to 10 mg tissue. The RNAqueous®-96 Total RNA Isolation Kit utilizes a 96-well plate format for high-throughput RNA isolation from 100 to 2 x 106 cells or 0.1 to 1.5 mg of tissue. The RNAqueous®-4PCR Total RNA Isolation Kit is designed for RNA isolation from small tissue samples (0.5–75 mg) and small- to medium-sized cultured cell samples (~100–107 cells).
No, please follow the RNA isolation methods described with the Tempus® system. The collection tubes are not compatible with the RiboPure™ kit.
Its composition is 0.1 mM EDTA in nuclease-free water.
The former (Cat. No. AM1928) is for isolation of RNA from human blood and the latter (Cat. No. AM1951) is for isolation of RNA from mouse and rat blood. Both kits have the same columns but differ in protocol and the wash 1 buffer, wash 2/3 buffer, and sodium acetate solutions. We do not recommend using the mouse kit for human blood samples. The mouse kit accommodates the difference in viscosity of mouse/rat vs. human blood and also the higher mouse and rat blood RNA yield. The mouse kit allows recovery of either total RNA containing small RNAs or total RNA depleted of small RNAs based on which protocol in the manual was followed. With the RiboPure™ Blood Purification Kit, using the standard protocol in the manual, you can isolate total RNA depleted of small RNAs, but with an alternate protocol, you can isolate total RNA containing small RNAs. Alternatively, if you need small RNAs alone, then you should follow the above alternate protocol for isolation of total RNAs containing small RNAs, and then follow Section IVA in the mirVana miRNA Isolation Kit manual (Cat. No AM1560).
RNA recovered using the LeukoLOCK™ Total RNA Isolation System typically contains less than 10% of the amount of reticulocyte-derived alpha- and beta-globin mRNAs present in typical mRNA samples from unfractionated whole blood. The isolated RNA is specially suited for gene expression profiling, as it contains a lower proportion of globin mRNA. We sell LeukoLOCK™ Fractionation and Stabilization Kit (Cat. No. AM1933) for blood collection and stabilization. You can then use LeukoLOCK™ Total RNA Isolation Kit (Cat. No. AM1934) to isolate RNA stabilized on the LeukoLOCK™ filters. Cat. Nos. AM1934 and AM1933 are available together, packaged in a single kit as the LeukoLOCK™ Total RNA Isolation System (Cat. No. AM1923).
RNA yield is typically 10–20 µg from 10 mL of blood. RNA quality depends on the quality of the blood. Typically, the RNA integrity number (RIN) value is around 9, and the 28S/18S ratio is around 1.5.
No. The kit has not been validated for less than 3 mL of human blood. It is best to use 9–10 mL blood.
The LeukoLOCK™ Total RNA Isolation System has been tested only for human blood.
No, they are based on different chemistries.
We have processed blood stored with heparin with the LeukoLOCK™ Total RNA Isolation System. The RNA looks fine. But we have not tested it for any downstream applications. We discourage your use of heparin, as heparin notoriously inhibits downstream applications such as RT-PCR.
Here is a list of DNA/RNA Purification replacement buffers we offer as standalone.
Yes, we offer our Cells-to-CT™ kits that allow you to bypass RNA purification. Read more here.
Please visit this webpage to see the cell lines we have tested. There is no reason why the Cells-to-CT™ system shouldn’t work with any cell line. However, due to differences in cell size and composition, the maximum number of cells per lysis reaction may be slightly different for different cell lines. You can test for inhibition and minimal sample input using the TaqMan® Cells-to-CT™ Control Kit.
We have tested the reagents that are stored frozen with five to ten freeze-thaw cycles and have seen no effect on CT values. Up to five freeze-thaw cycles for the lysate samples have not had any significant effect on gene expression data.
We do not recommend normalizing to an endogenous control, due to the biological variation and transcriptional noise exhibited by single cells. Because of this variation, normalization can actually increase the spread of calculated expression levels in single cells.
You can place samples at room temperature for up to 30 minutes following lysis, and up to 2 hours after adding stop solution. You can freeze cell lysates, cDNA, and preamplification samples for future processing.
No, there are no special considerations for working with GC-rich genes.
We have not used it on plant tissue internally. When working with plants, we suggest one of the following standard homogenization methods: (1) a motorized homogenizer, (2) stainless steel bead beating, or (3) grinding tissues in liquid nitrogen using a mortar and pestle.
Yes. Cells-to-CT™ kits are compatible with multiplex qRT-PCR assays. If a large number of targets are being tested, we recommend combining them with TaqMan® Assays.
Cells-to-CT™ technology features a unique method for lysing cultured cells while removing genomic DNA and preserving RNA integrity. Therefore, if you follow the lysis/DNase treatment steps in the protocol, genomic DNA contamination will not be an issue for your qRT-PCR.
Yes, Cells-to-CT™ kits can be used with TaqMan® Low Density Arrays.
Yes, as shown in the graph below, both the Power SYBR® Green Cells-to-CT™ Kit and the Fast SYBR® Green Cells-to-CT™ Kit were compared to a traditional RNA purification method followed by real-time PCR analysis. Both kits show equivalent performance to results obtained using purified RNA over a broad set of gene targets. Read more about the SYBR® Green Cells-to-CT™ kits here.
No. However, the SYBR® Cells-to-CT™ reverse transcriptase will work with the TaqMan® mastermixes (but not the other way around).
Here are the potential stopping points:
• At the Cell Lysis step after addition of the Stop Solution and incubating for 2 minutes at room temperature. Do not allow lysates to remain at room temp. for longer than 20 minutes after adding the Stop Solution. Lysates can be stored on ice for a maximum of 2 hours, or at -20 degrees C or -80 degrees C for a maximum of 5 months.
• At the Reverse Transcription (RT) step after assembling the RT reaction. Once assembled, mix reactions gently, then centrifuge briefly to collect the contents at the bottom of the reaction vessel, and store at 4 degrees C for up to 4 hours.
• Completed RT reactions may be stored at -20 degrees C.
The TaqMan® Gene Expression Cells-to-CT™ Kit can accommodate 45% of the total reverse transcriptase reaction volume as cell lysate.
While we have not tested this in house, the following paper did use our kit on cells infected with hepatitis C virus:
Triyatni M, Berger EA, Saunier B (2011) A new model to produce infectious hepatitis C virus without the replication requirement. PLoS Pathog 7(4)::e1001333.
Please use the selection guide to view the kits we offer for mRNA purification, as well as the differences between them. Read more about our Dynabeads® mRNA kits in the Dynabeads webpage.
RNAs less than 200 nt are lost using the columns in the RNAqueous family of kits. These kits are not suitable for isolation of 5S rRNA or tRNA. The RNAqueous-Micro Total RNA Isolation Kit does, however, offer a modified protocol to allow isolation of miRNA from the sample.
Please use the selection guide to compare our kits for miRNA isolation.
For recovery of miRNA of formalin-fixed samples, we recommend using RecoverAll Total Nucleic Acid Isolation Kit for FFPE. You can isolate total and miRNA using the RecoverAll Total Nucleic Acid Isolation Kit for FFPE, then use that prep for enrichment of miRNA using the enrichment protocol described in the instructions for the miRVana kit. For unfixed LCM samples, you could use an RNAqueous kit.
No, unfortunately, small RNAs will be lost using this purification method due to the low molecular weight cutoff from the column (~200 bp).
Yes, using a modification of the Megaplex Pools for microRNA Expression Analysis Protocol (P/N 4399721 Rev. B). In this protocol, scale the reverse transcription and preamplification reactions to include all of the cell lysate.
Yes. You will need to follow the alternate protocol, available in the following link.
The Poly(A)Purist Kit and MicroPoly(A)Purist Kit use oligo(dT) cellulose-based selection, while the Poly(A)Purist MAG kit uses oligo(dT) magnetic bead-based purification. The Poly(A)Purist Kit and Poly(A)Purist MAG Kit are used with total RNA preparations, while the MicroPoly(A)Purist Kit can isolate mRNA from a total RNA preparation or from small amounts of tissue or mammalian cells directly.
Yes, you can add a tenth volume of 3 M NaOAc before doing an ethanol precipitation.
Click to review the RiboMinus Workflow.
With regard to species specificity, the following organisms have 0 mismatches for the LSU/SSU probes (LSU (28S) / SSU (18S) Probe perfect matches). This means the probes will remove the 18S and 28S sequences from the following species.
Species from the Land | Species from the Sea | Plants |
Human, mouse, rat, frog, rabbit, cow, pig, chicken, Drosophila,* Caenorhabditiselegans, midge, mosquito, yeast (Saccharomyces cerevisiae, Schizosaccharomyces pombe) | Sea squirt, coelacanth, lancelet, eel, salmon, sturgeon, ratfish, lamprey, brown plankton, zooplankton | Arabidopsis thaliana, Brassica napus, rice, tomato, Humulus lupulus, Zea mays, wheat, soybean, pine, aspen |
* The 28S and 18S probes in this kit respectively align 100% to the Drosophila 18S and 28S rRNA sequence. However, there are reports suggesting Drosophila (insect) 28S rRNA split into 2 smaller fragments co-migrating with 18S. The exact split site is not identified yet. But based on customer feedback, this kit does not remove the split 28S rRNA completely. We have not tested Drosophila samples with this kit.
The 5S and 5.8S sequences are more divergent, and thus the best probes possible have reduced species breadth:
5S: zero to 1 mismatch: human, mouse, rat, frog, chicken, Drosophila, C. elegans, A. thaliana, Z. mays
5.8S: zero mismatches: human, mouse, rat
The RNA is easily quantitated using UV absorbance at 260 nm or a Quant-iT RNA Assay Kit. To verify rRNA depletion, electrophorese your sample on an agarose gel or use an Agilent® 2100 Bioanalyzer. Agarose gel electrophoresis should show depletion of 18S and 28S rRNA bands compared to a control sample. Absence of contaminating DNA and RNA degradation may also be confirmed by agarose gel electrophoresis. The efficiency of rRNA depletion in the purified RNA, RNA degradation, and RNA concentration can also be analyzed using a bioanalyzer.
We offer the following kits for this purpose:
Yes, for this purpose, you may take advantage of these products:
You would have to separate the virus from the cells prior to isolation to avoid contamination of the sample with cellular nucleic acids.
Here is a list of DNA/RNA Purification replacement buffers we offer as standalone.
For Research Use Only. Not for use in diagnostic procedures.