From: Damien Broderick (d.broderick@english.unimelb.edu.au)
Date: Sat Oct 06 2001 - 22:01:21 MDT
At 01:41 PM 10/6/01 -0400, John K Clark wrote:
>In the Oct. 5 issue of the journal Cell there is a report that the negative
>effects of short telomeres are not a function of average length as had
>been thought but a function of the shortest telomere in a cell.
Actually, I think this has been taken for granted for a while. It seems to
me to correspond interestingly with this earlier announcement:
==========
June 15, 2001; University of Texas Southwestern Medical Center; Dallas, TX
-- A discovery by UT Southwestern Medical Center at Dallas scientists that
genes near human telomeres can be silenced may help explain how and why
humans age. [...]Dr. Jerry Shay and Dr. Woodring Wright, UT Southwestern
professors of cell biology, report in today's issue of Science that human
cells can exhibit Telomere Position Effect (TPE), a mechanism by which
genes near telomeres can be turned off, and that the strength of gene
silencing is proportional to the length of nearby telomeres.
=============
So the shortest telomere of 92 in a nucleus is the one that will first mung
its adjacent codons; if these are crucial, the cell is in trouble.
On the other hand, I gather that the most crucial genes seem to be
preferentially located near the middle of DNA strands.
Damien Broderick
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