4 replies to this topic

[manofsan]

Read this:

http://www.betterhum...77/Default.aspx

So the SIRT1 is believed to be associated with cell division, and knockout of SIRT1 has been shown to cause unlimited cell replication.

What's happening here? What about the telomeres? Does SIRT1 cause associated production of telomerase to keep the telomeres happy?

What about this bit about "chronic response to oxidative stress"? How does SIRT1 help in this regard?

[spiritus]

Let me quote prometheus "This suggests that SIRT1 could be a DNA damage response regulator."

So in subjects without the SIRT1 gene, their bodies would not respond to DNA damage in the same way or at all.

If this was implemented in humans, the gene taken away... then DNA damage could perhaps happen without response. Could this lead to a painfull an agonizing death?

Another quote from prometh "Paradoxically, when this gene is overexpressed in yeast and C. elegans it extends lifespan."

I think I have a general idea of how it extends the lifespan. When it is overexpressed perhaps it allows better response to DNA damage, thus extending life.

Complete lack of it allows much longer life extention. Why? Perhaps it just allows a certain ignorance about cell damage occuring. The cells can continue to replicate in an infinite matter. Perhaps the death is when the cells are so badly damaged that they can no longer continue to work.

This is just a shot in the air, but it sounds pretty sweet to the ears. So, perhaps a genetically engineered gene that allows infinite cell replication while maintaining those cells is in order for the ingredients of the fountain of youth.

I need to know more about the condition of the yeast cells which were removed.

If you are confused by this, you haven't read the article on yeast living 6x longer.

[Mind]

Another study linking SIRT1 to longevity

Molecular biologist Sandy Westerheide of Northwestern University in Evanston, Ill., and her colleagues found that the heat shock response in human cell lines is regulated by Sirtuin 1, or SIRT1, an aging-related protein. It’s the first evidence linking SIRT1 to the protein-protecting heat shock response.

“This is a very interesting and insightful study,” comments Raul Mostoslavsky, a cell biologist at the Massachusetts General Hospital Cancer Center and Harvard Medical School in Boston. “We knew that Sirtuin 1 had many roles in longevity. It’s remarkable that it also affects heat shock response.”

The study focused on individual cells, but for whole organisms the finding could shed light on a link between stress and life span. “A little bit of stress can actually prolong life,” says molecular biologist Richard Morimoto of Northwestern, a study coauthor. Mild stress activates the heat shock response but does not harm the cells, he adds.

Edited by Mind, 26 February 2009 - 09:36 PM.

[Razor444]

A Remarkable Age-Related Increase in SIRT1 Protein Expression against Oxidative Stress in Elderly: SIRT1 Gene Variants and Longevity in Human

 

Aging is defined as the accumulation of progressive organ dysfunction. Controlling the rate of aging by clarifying the complex pathways has a significant clinical importance. Nowadays, sirtuins have become famous molecules for slowing aging and decreasing age-related disorders. In the present study, we analyzed the SIRT1 gene polymorphisms (rs7895833 A>G, rs7069102 C>G and rs2273773 C>T) and its relation with levels of SIRT1, eNOS, PON-1, cholesterol, TAS, TOS, and OSI to demonstrate the association between genetic variation in SIRT1 and phenotype at different ages in humans. We observed a significant increase in the SIRT1 level in older people and found a significant positive correlation between SIRT1 level and age in the overall studied population. The oldest people carrying AG genotypes for rs7895833 have the highest SIRT1 level suggesting an association between rs7895833 SNP and lifespan longevity. Older people have lower PON-1 levels than those of adults and children which may explain the high levels of SIRT1 protein as a compensatory mechanism for oxidative stress in the elderly. The eNOS protein level was significantly decreased in older people as compared to adults. There was no significant difference in the eNOS level between older people and children. The current study is the first to demonstrate age-related changes in SIRT1 levels in humans and it is important for a much better molecular understanding of the role of the longevity gene SIRT1 and its protein product in aging. It is also the first study presenting the association between SIRT1 expression in older people and rs7895833 in SIRT1 gene.
 

 

 

Unfortunately, the rs7895833 SNP isn't analysed with 23andMe.com.