Cells and Aging (fwd)

Sydney SHALL Sydney.Shall at esbs.u-strasbg.fr
Thu Mar 11 10:15:14 EST 1999

Aubrey de Grey wrote:

>Sigh.  Choosing when to worry and when not to is exactly what you are
>being criticised for.  The knockout mice are on current evidence by far
>the most powerful argument against the relevance of telomere shortening
>to aging, and the more you downplay them the more you marginalise your
>views.  The theory that shortest telomere length does not fall in the
>first five generations of knockout mice is still unfalsified, I agree
>(as I have previously).  That doesn't make it true, and the fact that
>the sixth generation is suddenly in such trouble argues against it.
I did not follow that last properly.  The important observation is that the
cells in the TR KO mice DO show cell senescence, even though it clearly
cannot be ascribed to the telomeres being too short.  When the animals got
to the 6th generation, the telomeres fell off and chromosome
disintergration occurred, I suppose.  This says only that you MUST have
telomeres to survive.  It seems to me that the essence of the hypothesis of
Calvin Harley is that telomere shorrtening is what tells a cell WHEN
exactly it will stop dividing.

I should add the character of a senescenct cell is a little different from
a cell that has stopped becquse of DNA damage; but of course this is not a
fatal criticism

Sydney Shall

Dr. Sydney Shall
Ecole Superieure de Biotechnologie de Strasbourg
Boulevard Sebastien Brant
F-67400 Illkirch, FRANCE
TEL:+33 388 88 65 69 FAX:+33 388 88 65 43
E-Mail:sydney.shall at esbs.u-strasbg.fr

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