Formaldehyde, hybridization, and Northern blots

Klaus Salger salger at
Tue Jul 19 13:37:03 EST 1994

Joel Huberman (camhuber at wrote:
: Dear Netters,

: 	To size-fractionate RNA prior to Northern blotting, formaldehyde gels
: are frequently used.
(stuff deleted)
: I would like to know whe-
: ther the formaldehyde reaction is fully reversed under standard hybridization
: conditions, or is there a possibility that use of a formaldehyde gel leads to
: less efficient hybridization than would use of a standard gel or a different
: type of denaturing gel, such as a formamide gel?

Dear Joel,
here's an alternative method for RNA Gels.
It was published in NAR v21 n11 p2783 by Pelle and Murphy.
Run your RNA in a 10mM NaPO4 buffer which has to be recirculated
to prevent the formation of a pH-gradient. That's all. This
works really perfectly without the use of hazardous substances like
formaldehyde, formamide,...
See the paper for details.

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