DNase I digestion - how long the fragments are at the end??? (May/07/2009 )

hello out there,

have a question about dnase digestion: after performance of standard dnase I digestion of my RNA preparation, how long are the DNA fragments (bp) in there?

thanks in advance for help

~10 bp maybe?

James
Understanding Life One protein at a time...
www.lifetein.com

"on average producing tetranucleotides" (http://en.wikipedia.org/wiki/DNASE1)
don't know if that's true, though... DNAse1 cuts adjacent to C or T, that would be dinucleotides on average (or am I wrong?).
Cheers,
Minna

It depends on how much DNase I you add and how long you incubate it. Just run an aliquot of the digested in a gel to take a look. You will get two pieces of important info from the gel - 1) is all your RNA gone (most DNase I has RNase activity)? 2) is the DNA digestion gone to completion (if the degraded DNA fragments are <200bp, you are fine with RT-PCR). I always use minimal amount of DNase I and incubate at RT for 30-60min, RT-PCR always works.