Telomerase and Reality Testing

jarice at delphi.com jarice at delphi.com
Tue Oct 25 21:37:09 EST 1994


Domenick Venezia <venezia at zgi.com> writes:
 
>As far as I am aware no mammalian telomerase gene has yet been cloned.
>If I'm wrong please send the reference(s) via private email. 
 
I believe the original question was whether telomerase has ever
been exogenously applied to an organism to invesitgate it's effects.
I would imagine that two things are possible: the cancer rate would
increase, and the organism may live longer. Remember, many cell types
in the human body do not ordinarily divide. So even if telomerase was
successful with dividing cells, non-dividing cells would continue to
age and deteriorate.
 
There is a problem with the telomere theory of aging, however. If
the length of the telomere serves roughly as a limit to the number
of divisions a cell is capable of, how does one explain various
experiments that extend the life of an organism, for example:
 
> Particularly striking was a paper entitled "Pineal Cross-Transplantation in
> Mice (Old to Young and Vice-Versa) as evidence for an Endogenous "Aging
> Clock", quote: "A remarkable acceleration of aging and death was seen in the
> young mice grafted with an "old" pineal, while a very significant delay of agi
ng
> and death was observed in the old mice grafted with a "young" pineal gland."
> The old mice lived an average of 1021 days, while the young mice lived an
> average of 510 days. Control mice lived an average of 719 days.
 
In the case of the rats that lived longer, did the cells that divided
get a few extra divisions, and if so, was this extra life mediated by
telomerase? If the dividing cells did not get extra divisions, was the
young pineal gland somehow increasing the interval between divisions?
 
Jim Rice




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