From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Tue Jul 23 2002 - 13:04:52 MDT
On Wed, 17 Jul 2002, Jeff Davis wrote:
> Stem cells could determine how long we live
>
> http://www.eurekalert.org/pub_releases/2002-07/ns-scc071702.php
>
> How long we live could depend on how hardy our stem
> cells are. American researchers have found that mouse
> strains that live the longest have stem cells in their
> bone marrow that are particularly good at repairing DNA.
I contacted Gary Van Zant one of the people behind this work.
He sent me a paper that is in press. Their best estimates
for the genes on chromosomes 2, 3, 11, involved in regulating
the aging of the stem cell populations include Rad50, Ercc1,
bub1 and cdc25b. Rad50 and Ercc1 are DNA repair genes. Rad50
seems to be involved primarily in homologous recombination. Ercc1
seems to play a primary role in nucleotide excision repair.
Bub1 is involved in the assembly of the kinetochore
and deletion lesions in the Bub1 gene cause aneuploidy.
Cdc25b is another cell cycle regulatory gene.
The Rad50 possibility is quite interesting because it fits
in well with my see-saw theory of aging vs. cancer in
choosing the Non-homologus end-joining vs. homologous
repair pathway for DNA double strand breaks. Choose
NHEJ and the genome gradually becomes corrupted and
you get aging. Choose HR and recessive alleles that
were masked begin their ugly heads.
Get just the right balance in the stem cells and you retain
the pool longer and have a longer healthier life.
Robert
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