library screen problem

Andrew Cockburn afc at gnv.ifas.ufl.edu
Fri Apr 22 12:06:27 EST 1994


In article <01HBFXLJU802000383 at UNCVX1.OIT.UNC.EDU>, KORTE at UNCVX1.OIT.UNC.EDU (JOHN) writes:
> Dear netters,
>      A friend in the lab is trying to screen a phage library she initially
> incubates her probe with "junk" filters that have been exposed to lamda without
> an insert most of her probe sticks to this but not the specific library that
> she needs to screen....any thoughts as to why?  (We've eliminate the chance of
> a contaminating phage DNA.)
> 				Thanks in advance
> 					John

If she is using a plasmid probe, it is probably contaminated with bacterial
DNA.  There is *lots* of bacterial DNA in a phage plaque.

To eliminate this problem, she can either do what she does now (hybridize
out the contaminant) or purify her plasmid.  This means rebanding on CsCl
(not just one run), cutting the band out of a gel, or something equally
compulsive.  Just because there isn't enough bacterial DNA to see on a
gel doesn't mean that there isn't enough to cause problems.

Andrew Cockburn



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