sequencing gel won't stick to Whatman paper

[Anne Cahill]

jlight at SICKKIDS.ON.CA wrote:
> 
> After I run a sequencing gel (using 35S-dATP for labelling) I have a lot of
> problems getting the gel to stick to Whatman paper.  I don't fix the gel
> after the run, because I've found that it's not necessary to get good
> autorads.  Unfortunately, and perhaps because I skip the fixing step, my
> gels don't always stick when I overlay them with Whatman paper (sometimes
> they do, sometimes they don't).  I've tried spraying the gel with water and
> blotting off the excess with Kim wipes prior overlaying with Whatman, which
> helps sometimes, but it's no guarantee.  Sometimes part of the gel sticks
> and part doesn't, so the gel ends up ripping.  Advice from anyone who
> routinely transfers their gels without fixing would be greatly appreciated.


A tech in the lab taught me a great technique for transferring unfixed 6% 
acrylamide-urea sequencing gels to Whatman 3MM. Simply pry apart the 
plates leaving the gel on the bottom plate. Place a piece of dry 3MM 
paper slightly larger than the gel on top of the gel. Then the secret is 
to use the edge of a "collection plate rack" (Rainin's term for what I 
think of as a 16 x 5 hole solid bottom microcentrifuge tube rack) to 
gently "iron" or press the paper to the gel. Two or three passes 
smooth passes from top to bottom are enough to cover the entire gel. Then 
peel up the paper and the gel from the glass plate starting from one 
corner. As you start to lift check that the corner of the gel is stuck to 
the paper. When no rack was handy, I've used the edge of a Kimwipe box, 
although it's harder to exert even pressure on the gel because the box 
is less rigid. This method has never failed for me.

Anne Cahill, Ph.D.
The University of Chicago
Dept. Pharmacological and Physiological Sciences
acahill at drugs.bsd.uchicago.edu