Glyoxal/DMSO Northern

Joerg Kaemper J.Kaemper at
Mon Jul 6 11:45:26 EST 1998

For Northern analysis we are often using the Glyoxal/DMSO protocol to
run RNA-gels, followed up by blotting to positively charged Nylon membranes
using 20x SSC. Usually this protocol works fine, but in every 5th to 6th
blot only the bottom half of the RNA is transferred to the membrane; the
top half stays in the gel. We have never obtained this problem with
Formaldehyde gels. Of course we could switch back to Formaldehyde gels,
but the people in the lab favour, despite the set-backs, the DMSO/Glyoxal
method, because it gives sharper bands and is less toxic.
We have the wildest hypotheses why only the bottom-RNA is transferred to
the membrane, but none is really satisfying.
Has anybody observed something similar, or has somebody an explanation
(or wild hypothesis, we do collect those) for the effect???
Thanks for replying, Joerg

Joerg Kaemper
Institute of Genetics
University of Munich

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