Freeze and Squeeze

[Glen Shearer]

Ann,

We do two methods of freeze/squeeze.

1.  Stain gel & cut out band --> freeze agarose cut-out in -20C freezer
for about 30 min or in 
   -70 freezer for about 5 min.--> put frozen chunk on a square of
Parafilm and fold Parafilm around the
   agarose--> squeeze firmly with fingers and a few drops of liquid will
dribble out the crease of the parafilm
   into a waiting microfuge tube.  We often use this liquid directly for
random primer labeling or add sodium 
   acetate (final of 0.3 M) and ethanol ppt. before use.

2. The second method is to stain and cut out band and put it in a small
microfuge tube.  Freeze the whole tube
   as above--> remove from freezer and spin in microfuge on high speed-->
the agarose will be 'crumbly' 
   and will form a loose pellet--> carefully remove the aqueous soup that
has your DNA in it--> use directly
   or ethanol ppt. as above.

Both methods work quickly and generally yield 50% to 75% in our lab.

Let me know how it works for you.
Glen

[gshearer at whale.st.usm.edu]

In article <4p9vqk$gu1 at swen.emba.uvm.edu>, ayezersk at gnu.uvm.edu (Ann M.
Yezerski) wrote:

> Does anyone have the standard protocol for "Freeze and Squeeze" to remove 
> DNA from an agarose gel?  If so, e-mail me at ayezersk at moose.uvm.edu.  
> Thanks in advance!
> 
> Ann Yezerski