storing RNA at -20C? - (Feb/21/2010 )

okay, so the facility where i work unfortunately does not have an -80 C freezer at the moment. it does have an -20 C freezer. i am doing my RNA isolations there for microarray work. I know that RNA is supposed to be stored at -80 C, so this is really unfortunate for my experiment.
how long can RNA be stored at -20 C?
alternatively i could drive it over to another facility with an -80 C freezer - but that would be like 30 minutes in a car. any methods of lowering the temperature while transporting it? dry ice?

thank you!

oh, by the way, there's this thing called RNAstable which supposedly allows you to store RNA at room temp - does anyone have experience with it?

thanks,

The reason for storing at -80 is not the RNA stability, it is to slow down any RNases around. If your RNA is of sufficient purity, it should be fine at -20.

we use this product called RNAlater with cells. it works quite well, we harvest cells, add RNAlater, and freeze them away at -20 or -80. the RNA is good for weeks.

hi there,

you can also store RNA in salt and ethanol until you go back to your lab and then precipitate it for your microarray experiments. RNA in ethanol is stable even at RT for considerably longer than in water. Its quite easy than cheaper than spending much on matrix like RNAstable if you have large number of samples.RNAstable is good...I've tried RNAstable for a month or so and ethanol for over 2 weeks at RT and RNA was still intact...if ethanol does the same for half the period at almost no cost, why bother?!!

Dry ice is the best way for long transport, but as you say its 30 min, you can as well do that in a -20 mini cooler or even normal ice!