extrachromosomal DNA circles

Dr. Sydney Shall sydney.shall at kcl.ac.uk
Wed Apr 25 06:17:57 EST 2001

Randall Parker wrote:

> Luval,
> Are these circles found in post-mitotic cell types? Remember, if telomeres
> shorten as a result of cell division and then the parts removed are what
> cause the formation of these circles then you wouldn't expect to find them in
> nerve or muscle or other post-mitotic tissue.
> On Mon, 09 Apr 2001 23:03:30 -0400 esteemed Iuval clejan did'st hold forth
> thusly:
> > I found a reference from 1984 (S. Goldsteinn and RJS Reis, in molecular
> > basis of aging, A.K Roy and B Chatterjee eds, p1) about EDCs in human
> > fibroblasts. I did a citation search and found several later refereces
> > and more work on this which I haven't read yet (except for the Guarente
> > et al work on ERCs, which I have read, but had thought was only
> > applicable to yeast). Does anyone seriously think that this form of junk
> > might be causative in aging? There was one article whose abstract said
> > that these circles come from tellomeres. Maybe short (hence more likely
> > to be uncapped) telomeres are more likely to give rise to these circles.
> >

I think that these circles probably come from internal sequences.  The telomere
should yield linear sequences or aberrant sequences.  But with the new structure
of telomeres I suppose it might be possible to get circles from telomeres.



-- Dr. Sydney Shall, Department of Molecular Medicine, GKT Schools of Medicine,
The Rayne Institute,
123 Coldharbour Lane, LONDON, SE5 9NU, TEL: 020 7848 5901; FAX: 020 7733 3877
E-Mail: sydney.shall at kcl.ac.uk


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