Telomeric Theory of Aging
ufotruth at ix.netcom.com
ufotruth at ix.netcom.com
Wed Aug 19 19:51:50 EST 1998
On 19 Aug 1998 22:40:08 GMT, excelife at earthlink.net (Excelife) wrote:
>The gene for telomerase is already encoded in the DNA but when most cells
>terminally differentiate that gene is no longer expressed. As noted below,
>by Joseph Strout, mice, particularly mus musculus, may not be the best
>candidate to test this experiment. Telomeric length in these mice are not
>only regulated by telomerase but also by an unrelated genetic component on
>chromosome 2.(Proc Natl Acad Sci U S A 1998 Jul 21;95(15):8648-8653 "Telomere
>length regulation in mice is linked to a novel chromosome locus.")
Can you give any more information about this unrelated genetic
component that also regulates telomere length in these mice?
>Many other mammals more closely compare to the human model of telomeric
>shortening leading to cellular senescence and presumed aging of the organism.
>Our knowledge of how to intervene in age related expression of specific genes
>is extremely limited so methods to re-activate the telomerase gene are not
But could we probably insert the telomerase gene to make the cells of
an organism immortal just like organizations such as GERON have done
with individual cells? GERON has made cells immortal without
re-activating the telomerase genes already in the cells. Could we do
the same with a whole organism?
>However, extra-nucleic expression of factors that can maintain telomeric
>length have been demonstrated. First by utlizing the RNA components
>associated with telomerase, (Nat Genet 1997 Dec;17(4):498-502 "Reconstitution
>of human telomerase with the template RNA component hTR and the catalytic
>protein subunit hTRT".) Secondly, dispersed DNA coding for the T2AG3
>telomeric repeats has been found in immortal cells not expressing
>telomerase,(Biochem Biophys Res Commun 1998 Jul 20;248(2):223-227 "Release of
>telomeric DNA from chromosomes in immortal human cells lacking telomerase
This is all very interesting. Thanks for the information. I just wish
I had a doctorates degree in molecular biology so I could understand
more of it. :-)
>Utilization of these procedures in mammals that age more like humans may
>answer the question of whether extending telomeric length in vivo will also
>extend the life span of the organism.
Let me ask you a few questions. My mind is buzzing with them. If you
could answer the following questions i would really appreciate it.
Can you tell us more about how mice age?
Do they NOT run out of telomeres before they grow old and die?
Or do mice "grow old" and die even though they have long telomeres?
If mice DO "grow old" and die without their cells growing old
individually or becoming senecent then what in the heck is making
their dividing cells die?
>Possibly, but no definitive study has been done to determine whether
>telomeric shortening is a causative factor in the death of mice. The long
>telomeres of of mus musculus, the telomerase knock-out mice studied by Dr. C.
>Greider and the fact that mouse cells do not experience telomeric related
>senescence do suggest a different progression of cellular development but do
So what are you saying?
Do mice cells eventually go into a senecence after a certain number of
divisions even though they have long telomeres? If so what could be
making them go into senecence.....
Sorry for all the questions but they are just buzzing through my head.
Thanks for putting up with them.
>not described any alternative cause of aging in mice. In fact one study of
>mouse telomeres shows that some chromosomes have significantly shorter
>telomeres than the other chromosomes, (Proc Natl Acad Sci U S A 1997 Jul 8
>94:14 7423-8 "Telomeres in the mouse have large inter-chromosomal variations
>in the number of T2AG3 repeats"). Yeast studies have shown that the "loss of
>a single telomere results in cell-cycle arrest and chromosome loss", (Nat
>Genet 1998 Jan 18:1 76-80).
>Without further research we cannot rule out telomeric loss as being a
>causative factor in the aging of mice.
Thanks very much for all of the information. If you could answer my
questions I would greatly appreciate it. I apologize for the number of
questions but they are all buzzing through my head.
Take care and have a great day. Keep up with great work with Lifeline
>Thomas Mahoney, Pres.
>Lifeline Laboratories, Inc.
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