RNAse Problems

[John Thompson]

Floating out of the well is indeed usually a symptom of residual EtOH.
But probably unrelated to your RNAse problem.  Consider that RNAse A
alone is generally not sufficient to reduce your RNA completely to
NTs.  Some short oligos will remain. Try adding a dash of RNAse T1 to
the mix.  I agree the possibility that it might be DNA is plausible
too.

Yours,
John Thompson
Merck & Co.


Rob Kirkpatrick <kirkpat at cc.umanitoba.ca> wrote:

>Does anyone know the common cause(s) of inhibition of RNAse in DNA
>preps?  The DNA was prepared from Concert columns and repeatedly fails
>to digest with RNAse.  The RNAse batch works on other samples but not
>this one.  I also seem to have some problem with loading this DNA on a
>gel to check it - it wants to float up and out of the wells.  I don't
>know if the problems are related or not.  I've considered the presence
>of residual ethanol as a problem but haven't come to a conclusion on
>that yet.  The DNA sample is about 1.5 mg/ml and the RNA band is easily
>visible but quite faint in comparison to the DNA.  I think that is about
>all the info I have.  Any help would be appreciated.
>
>Thanks,
>
>Rob