RNA storage

Jim Hutchins hutchins at fiona.umsmed.edu
Thu Sep 7 20:40:32 EST 1995

Kimberly Walker PhD (kwalker at umabnet.ab.umd.edu) wrote:
: Is there a proper way to store RNA after I have extracted it?
: I have been repeating preps because I figured it was labile.

: Kim

Asbestos underwear on.

Maybe I'll get flamed for this, but it is my *opinion* (not based on
research, or actual observations, mind you) that most RNA degradation
occurs while the RNA is thawing, or sitting out at room temp, either before
or after you put it in the freezer.  Most people store their RNA in 70% EtOH
at -80 deg C, and in our hands the RNA is stable for quite some time that
way IF no RNAases were introduced before storage.

The only support I could muster is Chomczynski (NAR 20[14]:3791-3792, 1992)
where he showed that storage of RNA in formamide eliminates degradation.
That works too, but is not suitable for some purposes (e.g., anything where
RT is the next step).  I would bet that formamide inactivates RNAases--any
support here?

By the way, I have done the experiment where I stored RNA in formamide and
then tried to remove it with the SpeedVac.  It doesn't work, so don't make
the same mistake :-).  If we need the RNA for a gel, we store it in formamide
at -80; if we need it for RT, we store it in 70% EtOH and SpeedVac it before
use.  You did not ask, but should be aware, that any trace of EtOH messes up
RT.  So you have a Hobson's choice: if it's too dry, the RNA won't go back
into solution easily; if it's not dry enough, traces of EtOH kill the RT

More than you wanted to know.  Hope this helps.
Jim Hutchins
Assoc Prof Anatomy, Asst Prof Neurology (Research), Univ Mississippi Med Ctr
http://fiona.umsmed.edu/~hutchins/    ***    E-mail:   hutchins at umsmed.edu
``It became necessary to destroy the town in order to save it.''--American
infantry officer firing on Ben Tre, Vietnam, 2/8/68

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