Typically, in order to isolate high quality RNA, the tissue has to be processed immediately after harvest. Ambion's patented RNAlater™ Tissue Collection: RNA Stabilization Solution makes it possible for researchers to postpone RNAlater® for days, weeks, or even months after tissue collection without sacrificing RNA integrity (Figure 1). Since RNAlater inactivates all cellular enzymes, including RNases, RNA expression profiles can be "frozen" without immediate RNA isolation.


Figure 1. Quality of RNA Isolated From Tissue Stored in RNA later™ Solution. Fresh mouse tissues were dissected and stored in RNA later at 37°C for 1 day, room temperature for 1 week, or 4°C for 1 month. RNA was isolated using TRI Reagent® (MRC) and analyzed using denaturing agarose gel electrophoresis.

How do you use RNAlater?

Dissected tissue (< 0.5 cm in one dimension) is simply submerged in 5-10 volumes of RNA later at room temperature. RNA later is compatible with dissected tissue samples, eukaryotic and bacterial cells, and even plasma. The solution permeates the cells, stabilizing the RNA and "freezing" the RNA expression profile. The sample can then be stored in RNA later at room temperature for up to a week, stored at 4°C for a month, or stored indefinitely at -20°C without nucleic acid degradation. For RNA isolation, the tissue is simply removed from RNAlater and treated as though it had just been harvested. Most tissues can be transferred directly to lysis buffer and homogenized, although some hard tissues such as bone may require a more rigorous method of disruption. RNA can be isolated from RNA later-treated tissues using any of Ambion's RNA isolation kits.



Figure 2. Northern Blot of RNA Isolated From RNA later™-Preserved Tissue. Mouse tissues were dissected and stored in RNA later as indicated. RNA was purified from equal mass amounts of tissue using TRI Reagent® (MRC). Five µg of each RNA sample was Northern blotted. The blot was hybridized with 10 6 cpm/ml of a high specific activity probe for p53 and 10 6 cpm/ml of a low specific activity probe for GAPDH.

What can RNAlater do for you?

RNA later is an aqueous, nontoxic tissue and cell collection reagent that stabilizes and protects cellular RNA in intact, unfrozen tissue and cell samples. RNA later eliminates the need to immediately process samples or to freeze samples in liquid nitrogen for RNA preservation. Tissue pieces can be harvested and submerged in RNA later for storage without jeopardizing  the quality or quantity of RNA obtained after subsequent RNA isolation (1-4). RNA later can be added to tissue, cell pellets, cells in media,  or bacteria. The samples can then be stored frozen or at 4°C.

Treating tissue with RNA later can also preserve the tissue architecture, which is essential for histopathological analysis. Ellis et al (2002) found that treating breast tissue cores with RNA later prior to fixation allows optimal pathological interpretation and preservation of important diagnostic information.

References

  1. Dunmire V, Wu C, Symmans WF, Zhang W. (2002) Increased yield of total RNA from fine-needle aspirates for use in expression microarray analysis. Biotechniques 33(4): 890-6.

  2. Ellis M, Davis N, Coop A, Liu M, Schumaker L, Lee RY, Srikanchana R, Russell CG, Singh B, Miller WR, Stearns V, Pennanen M, Tsangaris T, Gallagher A, Liu A, Zwart A, Hayes DF, Lippman ME, Wang Y, Clarke R. (2002) Development and validation of a method for using breast core needle biopsies for gene expression microarray analyses. Clin Cancer Res 8(5): 1155-66.

  3. Florell SR, Coffin CM, Holden JA, Zimmermann JW, Gerwels JW, Summers BK, Jones DA, Leachman SA. (2001) Preservation of RNA for functional genomic studies: a multidisciplinary tumor bank protocol. Mod Pathol 14(2): 116-28.

  4. Bachoon DS, Chen F, Hodson RE. (2001) RNA recovery and detection of mRNA by RT-PCR from preserved prokaryotic samples. FEMS Microbiol Lett 201(2): 127-32.