Cathy Sprankle Sprankle at ciit.org
Thu Nov 16 17:23:05 EST 1995

In article <aquilla.1166668373I at emba-news.emba.uvm.edu>,
aquilla at salus.med.uvm.edu (Tracy Aquilla) wrote:


> >>The department I am joining has tissue samples that have been frozen
> >>away for years and they want me to do RT-PCR on the samples. The
> >>samples were not taken originally for molecular biology and so have
> >>been placed in non sterile clean tubes (not autoclaved though) and were
> >>flash frozen in liq N2 and stored at -20 and -80. Does anyone out there
> >>know how long samples can be kept frozen before analysis. Will the RNA
> >>have degraded? 

> >
> >You better throw away the samples stored at -20!
> I wouldn't follow this recommendation until you confirm that the RNA is too
> degraded to be of use. I've isolated excellent quality RNA from tissues
> stored at -20 for several months. I've also found on occasion that purified
> RNA stored in water at -20 for years was of acceptable quality for
> Northerns.

True, but I'd suggest running a test Northern blot to check the RNA before
doing any important experiments.  I've had RNA that looked great when I
ran it out on a gel (rRNA bands looked intact, lots of high MW material,
etc.), but when I probed for my message of interest, all I got was a
smear.  Good luck!

Catherine Sprankle
e-mail:  sprankle at ciit.org
Opinions expressed (such as they are!) are strictly mine and do
not reflect those of CIIT.

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