I am interested in sequencing/footprinting on relatively small
DNA sequences. A 20% denaturing PAGE gel will accomodate almost the entire
sequence, but the smallest fragments usually get very spread-out and the
very smallest zip right off the end of the gel. One person suggested
pouring a gel of variable thickness to create an electrical field gradient.
Large pieces would migrate faster, small pieces would migrate slower, relative
to their mobilities in a standard "flat" gel. This makes sense to me, and
I have seen examples of such gels. After checking searching the archives
for this group, I have seen nothing on this topic except a reference to
thermal gradient gels which may yield similar results.
I would like to see if anyone has had experience with E-field
gradient gels, or if anyone can give pointers to literature on the subject.
According to the person who recommended this technique, his lab used to
home-make the spacers out of nylon plastic sheets using a lathe. Can
anyone recommend a commercial supplier?
Thanks in advance for information. Please respond by Email to
welch at sc3101.med.buffalo.edu
Or reply via this newsgroup.
Roswell Park Cancer Institute