RNA extraction from nitrogen-frozen tissue - (Aug/11/2005 )
How long a tissue may be stored in liquid nitrogen before RNA extration? Some of my samples are stored since 2000!! Is there anyone who knows if I still can obtain a good-quality RNA (for subtractive library ou RQ-PCR)?
If it's stored in liquid nitrogen then I see no reason why you shouldn't be able to get quality RNA from the tissue (providing that the tissue was frozen immediately upon isolation). I consistently perform RNA extractions on plant tissue that was snap-frozen in liquid nitrogen, removed and placed in a sandwich bag, and stored in a -80 freezer 2 years ago with no loss in RNA quality.
i've mentionned it before and don't want to bore people too much, but i would recommend you to put 50°-preheated lysis solution in order to accelerate lysis step and reduce great RNA degradation.