Ian A. York wrote:
>> In article <01bbbfd6$9e62c400$21746a8d at meb_493a.cvrc.mcw.edu>,
> Joe Miano <jmiano at post.its.mcw.edu> wrote:
> >
> >If a transgene is stably integrated in a cell line through selection with
> >G418, why is continued G418 necessary with clonally-derived cells? It
> >seems that once the gene is integrated and cloned, no further G418 would be
> >necessary, n'est ce pas?
<stuff snipped to allow Netscape to post reply>
In all the stable transfectants I've ever tested, the transgene was notoriously
unstable. FWIW, here's my take on what's going on. Standard production of stable
transfectants involves illegitimate recombination to insert the transgene into the
recipient genome. There is probably some reason to think that this event will
occur more readily in an "unstable" region of the genome. DNA slides in, DNA
slides out. If there's no selection pressure, your homogenous population of
transfected cells quickly becomes heterogeneous, with the end result that the
cells still carrying the transgene after however many generations sans selection
become diluted out.
Just my 0.02.
----------------
John Watson
Bristol-Myers Squibb Co.
watson_j at bms.com
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