3 replies to this topic

[labgrl76]

Can anyone please tell me if microRNAs are isolated along with larger RNA molecules using the guanidinium isothiocyanate / caesium chloride centrifugation RNA extraction protocol?

I have previously extracted RNA from frozen cell line material using this method. I am now interested in microRNA and was wondering if my previously extracted RNA would also contain these small molecules.

[Fizban]

labgrl76, on Feb 1 2010, 10:48 PM, said:

Can anyone please tell me if microRNAs are isolated along with larger RNA molecules using the guanidinium isothiocyanate / caesium chloride centrifugation RNA extraction protocol?

I have previously extracted RNA from frozen cell line material using this method. I am now interested in microRNA and was wondering if my previously extracted RNA would also contain these small molecules.

General semi-serious answer (but basically true):
if you see RNA there WILL be microRNAs as well. If you don't see RNA microRNAs will be there anyway!
It's just to say that if you do not use something that specifically eliminates short RNAs you will almost surely find miRNAs in your total RNA. sometimes you can detect small RNAs even in bad quality RNA samples.
just give it a try
Fiz

[Gaetanodiitaly]

SEE

MicroRNA isolation and stability in stored RNA samples.

Mraz M, Malinova K, Mayer J, Pospisilova S.

Biochem Biophys Res Commun. 2009 Dec 4;390(1):1-4. Epub 2009 Sep 19. Review.

[Biodate]

Not all RNA isolation kits will isolate Total RNA including miRNA. The only kit I use for this purpose is from Norgen Biotek. Otherwise you must use a phenol based method