Northern background

Klaus.Matthaei at ANU.EDU.AU Klaus.Matthaei at ANU.EDU.AU
Wed Nov 17 17:19:45 EST 1993

With regard to Southerns we (and the FBI) have found that stripping in 55%
formamide, 2xSSPE, 1% SDS at 65*C for 60-90 minutes results in the cleanest
removal of probe and the least loss of target (i.e. can reprobe MANY times
e.g. 8-10 times).  

With regard to background from large probes we always acid depurinate the
probe to shear to about 500bp since this gives the best signal.  

When we see a huge  background on the top half of our blot i.e. high MW end
it is I believe due to a dirty electrophoresis tank that has been used to
run plasmids etc. i.e. DNA contamination in the buffer that then
electrophoreses into the gel.

Good Luck, Klaus
Klaus Matthaei
Gene Targeting
The John Curtin School of Medical Research
The Australian National University
E-mail: Klaus.Matthaei at

"Think twice - Do once"

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