Direct selection for GalE in E.coli
rafael at corona.med.utah.edu
Mon Mar 20 14:07:45 EST 1995
On Mon, 20 Mar 1995, Duncan Clark wrote:
> Why do I want a GalE delta(lac-proAB) host? If you use pUC18 in such
> a host with IPTG/Xgal etc the alpha complementation is lethal with
> phenylgalactoside. This gives a direct selection for whites. Just
> think, no phosphatasing and everything has an insert.
HA! You're not the first one in thinking of that.
Gossen et al. (1992) Application of galactose-sensitive E. coli strains as
selective hosts for LacZ- plasmids. NAR 20, 3254.
I think that you can get some other mutation that mimics the toxicity of
galactose, but I think happens at very low frequency. Others mutations
may be in the lacZ of your plasmid.
Why are not people using this system? You know, MBist are too lazy to
change techniques... and the X-gal system works pretty well.
Rafael Maldonado "You gave to a boy the job
Department of Human Genetics of a man. He's dead."
University of Utah
Salt Lake City, Utah 84112. USA. John Wayne
Rafael at genetics.med.utah.edu
Rafael at corona.med.utah.edu "No por mucho madrugar, amanece
Tlf: 801-581-4429 mas temprano"
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