E. coli lacZ complementation

[Chris Boyd]

In article: <199410141622.JAA23090 at net.bio.net> 
hwyckoff at ASRR.ARSUSDA.GOV ("HERBERT WYCKOFF") writes:
> 
> 
> I would like to modify an E. coli strain(MC1061) that is much used in
> our lab so that it can be used to perform blue/white color screening
> with alpha-complementing vectors.  I would prefer to do this without
> adding any antibiotic resistance to the strain.  If anyone knows of a 
        
> reference where this type of construction is described, I would 
> appreciate you sending me the citation. Thanks

to which MICHAEL BENEDIK replied:

> 
> MC1061 is a complete deletion of Lac. You have 2 options to make it
> into
> a blue white strain. 
> 
> 1) get the phi80 dlac phage used in JM83 or similar strains and make
> a lysogen of MC1061 with it.
> 
> 2) make a ProAB- mutant of MC1061 and then mate in the F'pro-lac
> episome
> used in JM101 or other such strains.
> 
> It would be the easiest to use an antibiotic marked episome because
> then
> no further strain constructions would be needed.
> 
> MICHAEL BENEDIK                                      BENEDIK at UH.EDU

In fact, this has already been done.  DH10B was made by Doug Hanahan
from MC1061, has lacZdeltaM15 and can therefore be used for the
blue/white test. It is also the strain with the highest attainable
degree of electrocompetence. See Grant, SGN et al., PNAS (1990) 87,
4645. Available from many labs, or as competent cells from GibcoBRL.

Chris Boyd        MRC Human Genetics Unit       ebmo78 at castle.ed.ac.uk
Western General Hospital /  Crewe Road / Edinburgh EH4 2XU /  Scotland