bernard at elsie.nci.nih.gov
Thu Jan 18 01:25:44 EST 1996
In article <4dirb7$i4j at scotsman.ed.ac.uk>, chrisb at hgu.mrc.ac.uk says...
[snip: (dam-, dcm- GM2163 doesn't appear to work)]
>Someone else mentioned that you need to propagate GM2163 on
>chloramphenicol to maintain the dam mutation (which is caused by a Tn9
>insertion). I disagree. The frequency of spontaneous perfect excision
>of Tn9 is negligibly low.
Yep, that was me but I was only following NEB's advice. I'm
glad to hear that you don't have to be as careful.
Can you (or anyone else who's familiar with transposons)
comment on the stability of the others used in host strains?
(eg. the Tn10 tetR in many F' factors and the Tn5 kanR used to
select for other genotypes). I realise that growing the bugs in
the presence of tet is necessary/advisable where Tn10/F' is
required but is it necessary to keep up kan selection when the
host has a Tn5 genomic marker? At the moment I select my competent
cells but don't always include kan in the maxiprep cultures (and
can't say that I've seen anything bad happening).
Also, does anyone select for the gyrA96 property - and how?
Bernard Murray, Ph.D.
bernard at elsie.nci.nih.gov (National Cancer Institute, NIH, Bethesda MD, USA)
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