How long can extacted total RNA last? - (Nov/14/2006 )

Hi, all!

I extracted the total RNA from some C. elegans sample about 1 month ago using the promega Total RNA extraction kit and then stored at -20 degree. Now I need some RNA again. I'm just not sure if the RNA I extracted a month ago is still OK to used for cDNA synthesis.

Thanks a lot for help!

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...why don't you just try it?

I think you should however store your RNA samples at -80°C for longer storage times; I guess -20°C for a month is no problem.

Cheers

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Hi,
I've stored RNAs at -80 for more than 2 years. A months at -20 should not affect it, unless you thawed it in between. You can use a very sensitive RT kit to do your cDNAs.

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Personally, I recommend you redo the RNA abstraction if you still have some sample. That's more safe right?

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that would be the best. But 1 month to -20 would be ok for some cDNA synhesis if the temperature of sample did not change too much. I mean if the freezer was jump at -10° for at least 2times, the RNA will damage. You may check little on agarose TBE gel and upload the picture if you want more insights.
As cDNA synthesis is "relative" high cost, i would test it by gel first.

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Thanks a lot! I'm pretty sure that the temperature was quite stable at -20 in the past one month. Therefore I presume that the RNA is ok. And I did the cDNA synthesis today and amplifying the target fragment tonight. Hopefuly tomorrow I can have a clue. If the PCR is not OK, I'll run the RNA on the gel and show the picture to you. Many thanks!

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One thing to watch for is many -20C freezers are frost free freezers. We recently put a thermal alarm in one of our frost free freezers and we found that it was quite often only -5C. Overall if you want to store RNA either store it at -80C or store it in formamide or in 70% ethanol.

Daniel

Better DNA sequencing traces

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Hello,
It may be obsolete at the first sight, but I remember that no frost freezers are not recommended for storages in mol biol, are they. Any updates in between?

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No

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Can get some more double negatives into this discussion

I think we need a better name than "non frost free freezer"

Daniel

Longer ABI sequencing traces

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