Posted on 11/18/2005 4:05:32 AM PST by PatrickHenry
Deleting the ‘anti-aging’ gene from yeast greatly lengthens life span, say USC molecular scientists.
A counterintuitive experiment has resulted in one of the longest recorded life-span extensions in any organism and opened a new door for anti-aging research in humans.
Scientists have known for several years that an extra copy of the SIR2 gene can promote longevity in yeast, worms and fruit flies.
That finding was covered widely and incorporated into anti-aging drug development programs at several biotechnology companies.
Now, USC molecular geneticists suggest that SIR2 instead promotes aging.
Their study, titled “Sir2 Blocks Extreme Life-Span Extension,” appears in the Nov. 18 edition of the biology journal Cell. The lead author is Valter Longo, assistant professor in the Leonard Davis School of Gerontology and the USC College of Letters, Arts and Sciences.
Rather than adding copies of SIR2 to yeast, Longo’s research group deleted the gene altogether.
The result was a dramatically extended life span – up to six times longer than normal – when the SIR2 deletion was combined with caloric restriction and/or a mutation in one or two genes, RAS2 and SCH9, that control the storage of nutrients and resistance to cell damage.
Human cells with reduced SIR2 activity also appear to confirm that SIR2 has a pro-aging effect, Longo said, although those results are not included in the Cell paper.
Since all mammals share key aging-related genes, the paper points to a new direction for human anti-aging research.
Longo proposes that SIR2 and possibly its counterpart in mammals, SIRT1, may block the organism from entering an extreme survival mode characterized by the absence of reproduction, improved DNA repair and increased protection against cell damage. Organisms usually enter this mode in response to starvation.
The long-lived organisms in Longo’s experiment showed extraordinary resilience under stress.
“We hit them with oxidants, we hit them with heat,” Longo said. “They are highly resistant to everything. What they’re doing is basically saying, ‘I cannot afford to age. I still have to generate offspring, but I don’t have enough food to do it now.”
Longo predicted that as molecular geneticists master the levers of aging, they will be able to design drugs that coax the body into entering chosen aspects of a starvation-response mode, such as stress resistance, even when food is plentiful.
If enough food is available, an organism might be programmed both to reproduce normally and to maximize its survival systems.
Longo urged caution in extrapolating the result to humans.
“We have been very successful with simple organisms,” he said. “Naturally, mammals are complex, and it will be a great challenge to get major life-span extension.”
A “really exciting” implication, Longo said, is that cells may be able to speed up their DNA repair efforts. All organisms have the ability to repair harmful mutations in their DNA, whether caused by age, radiation, diet or other environmental factors. Cancer often begins when DNA mutations outstrip a cell’s ability to remain differentiated.
Many researchers believe DNA repair systems are already running flat out. The organisms in Longo’s experiment say otherwise.
[Deleting a few paragraphs from the end. Geeky stuff. The newsy implications are above.]
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That's what I tried telling my girlfriend, just before she hit the road.
"Longo urged caution in extrapolating the result to humans."
Appropriate name
It would be ironic if the anti-aging genes also regulate weight. If, in nature, it is switch because of starvation, artificially inducing the switch would lead to a very, very long life, possibly with obesity as a result. In other words, you could live 300 years, but you have to be fat.
Sure it is. When God created Adam and Eve, they lived for hundreds of years. Over time, due to sin, genetics deteriorated and shortened our life spans. There's no evidence here of accidental improvement in life span.
Why, is there evidence that the SIR 2 gene wasn't present in ancient humans?
Over time, due to sin, genetics deteriorated and shortened our life spans.
Genes don't just deteriorate. Mutations can be benificial or detrimental - and genetic complexity can increase in subsequent generations.
There's no evidence here of accidental improvement in life span.
Accidental, no. Do to better health practices, nutrition, sanitation, vaccinations, etc. our lifespan is longer than at any time in recorded history.
Conversely, there's no evidence of an intentional improvement in life span as well.
Why, is there evidence that the SIR 2 gene wasn't present in ancient humans?
I would be interested if the SIR 2 gene is also present in the chimpanzee. If it is, maybe it's God's way of indicating that ID is bunk and Evo is the path to knowledge. Just a thought.
I hope I never see the day when people can arbitrarily extend their life spans to many times their natural length.
That would be a sad irony and a difficult choice for Paris Hilton I'm sure!
I'm not gonna try it. Let's get Mikey to try it.
Why, yes. I recently concluded a complete DNA analysis of both Adam and Eve, and there is evidence that the "SIR 2" gene was a mutation resulting from an apple they'd eaten that had some really nasty toxins in it.
The SIR 2 gene allowed them to live, but their life became butal, nasty, and short.
HAND
I don't think the idea of an "intelligent designer" is bunk, I just think it is bunk science.
In any case, if we could prove the gene was absent in early humans, it might the beginning of research indicating that people once actually did live longer (more analysis would be needed, of course...) All wildly speculative musings, though, at this point.
We agree. I stand corrected.
Why?
The bible record has longer lifespans. But then you reject some recorded history.
I demand you take the pill and join AARP!
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