Naked Science Forum
Life Sciences => Cells, Microbes & Viruses => Topic started by: Keri on 04/08/2006 02:07:56
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Hi! First-time forum poster, but I've been listening for a few months. I love the show, your accents, but mostly that you involve students below college age. Life habits are developed during that adolescence, and instilling an appreciation for science early is a marvelous thing. We need more science geeks in the world, if for no other reason that other geeks like me will have people to talk geek with!
Anyway, my question is about telomeres. Maybe you've answered this question elsewhere, but how do telomeres relate to aging? I understand that they are segments on the tips of chromosomes that are slightly 'worn' away with each cell division, so they're reasonable measures of the age of a cell, but how does that relate to the age of an organism?
Thanks,
Keri
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Welcome, Keri,
I am about to go to bed, so i will give a very cursory answer to this. Maybe someone else can fill in the details.
Basically, if the cells of an organism are having difficulty dividing, then the organism itself will have greater difficulty repairing damage to itself. Fr instance, if you have a cut on your skin, the skin cells need to divide to create new cells to fill the gaps. If there is a problem with cell division, then it will take linger to get these new cells to repair the gaps in the skin. This not only applies to the skin, but to every organ in the body that will be subject to the normal wear and tear of everyday life.
George
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Telomeres are the physical ends of linear eukaryotic chromosomes. They are specialized nucleoprotein complexes that have important functions, primarily in the protection, replication, and stabilization of the chromosome ends. In most organisms studied, telomeres contain lengthy stretches of tandemly repeated simple DNA sequences composed of a G- rich strand and a C-rich strand (called terminal repeats). These terminal repeats are highly conserved; in fact all vertebrates appear to have the same simple sequence repeat in telomeres: (TTAGGG)n. Often sequences adjacent to the telomeric repeats are highly polymorphic, are rich in DNA repetitive elements (termed subtelomeric repeats), and in some cases, genes have been found in the proterminal regions of chromosomes.
I found this below on wikipedia. Interesting.
The phenomenon of limited cellular division was first observed by Leonard Hayflick. Significant discoveries were made by the team led by Professor Elizabeth Blackburn at the University of California - San Francisco. In 1998, Geron Corporation developed techniques for extending telomeres, and proved that they prevented cellular senescence. Senescence is the phenomenon where cells lose the ability to divide.
Steven
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Also telomerase (the enzyme which "adds" the telomeres) is very active in embryonic development and (possibly?) very early childhood before it the gene is deactivated. (I think the exception is in the testes where the integrity of the DNA is clearly critical.)
I also remember reading that unwanted telomerase activation plays a key role in some types of tumor formation as it is one of the things required to give cells immortality.
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yes, telomerase is one of the most important genes in cancer, as you said, if it is active when it shouldn't be then telomeres are continuously repaired in cells that are meant to have a finite lifespan and they become immortal, helping the cancer progress.
Are YOUR mice nude? [;)]
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You mean the gene coding for telomerase, right? Telomerase is an enzyme.