From: Joao Magalhaes (joao.magalhaes@fundp.ac.be)
Date: Sat Sep 21 2002 - 11:56:06 MDT
Hi!
At 10:01 21-09-2002 -0700, you wrote:
>However the resistance does not appear to be due
>to any of the obvious antioxidant genes (similar to the
>confusing state of affairs right now with transgenic mice
>where mice overespressing various antioxidant genes do not
>show extended lifespans).
It is not confusing if you conclude that oxidative damage has nothing to do
with mammalian aging, which incidentally is becoming my position. As a
scientist, my approach is that we should observe the facts and then derive
hypothesis from the facts. Since there is no evidence that oxidative damage
causes aging in mammals; all experiments to test the oxidative damage
theory on mammals have failed, particularly Richardson's results are
incompatible with the theory; then perhaps the simplest explanation is that
the oxidative damage theory of aging is plain wrong.
Which leads us to:
> > Regulation of Aging by the SIR2 Gene
> > Leonard Guarente, Ph.D., MIT
>
>Leonard gave a very nice summary of the effects of the SIR2
>type genes regulating gene expression. These genes are
>histone deacetylase genes that function to turn off gene.
>These genes are found most/all complex organisms and overexpression/
>underexpression can lengthen/shorten lifespan of these organisms.
>The method may very well be universal -- but precisely *what*
>is being regulated may be very different in organisms
>from yeast to C. elegans. So gene silencing may be
>a very general mechanism in nature for controling longevity.
As I mentioned in earlier e-mails, I'm moving in favor of a DNA damage-type
theory of aging. I'm not sure yet, of course, but my bet on the causes of
aging would be something along the lines of DNA
methylation/silencing/chromatin structure. I read a few reviews lately on
how translation, DNA repair, and chromatin structure are connected. For
example, WRN (Werner's protein) forms complexes with proteins involved in
translation, DNA repair, and chromatin structure. I have a hunch that the
causes of aging are somewhere around there. I want to write a paper on this
but I still lack many details.
Thanks for the info, Robert. Best wishes.
Joao Magalhaes (joao.magalhaes@fundp.ac.be)
Website on Aging: http://www.senescence.info
Reason's Triumph: http://www.jpreason.com
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