Scientists identify protein that improves DNA repair under stress

Jun 16, 2011

Cells in the human body are constantly being exposed to stress from environmental chemicals or errors in routine cellular processes. While stress can cause damage, it can also provide the stimulus for undoing the damage. New research by a team of scientists at the University of Rochester has unveiled an important new mechanism that allows cells to recognize when they are under stress and prime the DNA repair machinery to respond to the threat of damage. Their findings are published in the current issue of Science.

The scientists, led by biologists Vera Gorbunova and Andrei Seluanov, focused on the most dangerous type of DNA damage – double strand breaks. Unrepaired, this type of damage can lead to premature aging and cancer. They studied how oxidative affects efficiency of . Oxidative stress occurs when the body is unable to neutralize the highly-reactive molecules, which are typically produced during routine cellular activities.

The research team found that human cells undergoing oxidative stress synthesized more of a protein called SIRT6. By increasing SIRT6 levels, cells were able to stimulate their ability to double strand breaks. When the cells were treated with a drug that inactivated SIRT6, DNA repair came to a halt, thus confirming the role of SIRT6 in DNA repair. Gorbunova notes that the SIRT6 protein is structurally related to another protein, SIR2, which has been shown to extend lifespan in multiple model organisms.

"SIRT6 also affects DNA repair when there is no oxidative stress," explains Gorbunova. "It's just that the effect is magnified when the cells are challenged with even small amounts of oxidative stress." SIRT6 allows the cells to be economical with their resources, priming the repair enzymes only when there is damage that needs to be repaired. Thus SIRT6 may be a master regulator that coordinates stress and DNA repair activities, according to Gorbunova.

SIRT6 does not act alone to repair DNA. Gorbunova and her group also showed that, in response to stress, SIRT6 acts on a protein called PARP1 to initiate DNA repair. PARP1 is an enzyme that is one of the "first responders" to and is involved in several DNA repair machineries. By increasing the levels of SIRT6, the Rochester team found that were able to more rapidly direct DNA repair enzymes to sites of damage and hasten the repair of double strand breaks.

The next step for Gorbunova and Seluanov is to identify the chemical activators that increase the activity of SIRT6. Once that discovery is made, Gorbunova said it may be possible to apply the results to therapies that prevent the onset of certain aging-related diseases.

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210
1 / 5 (1) Jun 16, 2011
Confirmation...at last!
During vigorous exercise the body repairs DNA breakage/damage.
While we sleep, primarily, our repaired DNA repairs our bodies. Now if we could just find a food supplement to handle telomere shrinkage and build to completion the experiment the Soviets did in the early sixties. The Soviets exploded a rocket in earth's atmosphere that contained several tons of water. The water remained liquid and was transparent to most radiation except UV rays, a huge cancer causer. Fix these two and the nagging social issues of food and wealth distribution, racism, sexism, global and regional armed conflict, impending climate change, water table pollution and depletion, over-use and abuse of antibiotics and prescription drugs, alcoholism, rampant AIDS and other STDs oh, and fix the global economy and hey, we could add about another 200 active, quality years to the average human lifespan...possibly more. I think I'll get on this :-)
word-to-ya-muthas
Telekinetic
1 / 5 (5) Jun 16, 2011
In a very short time, a Russian biochemist named Skulachev will
make his mitochondrial protectant available to all. It's called
SkQ1, and will be the most effective anti-aging compound to date.
200 year lifespan? Doubtful, but Kurzweil's strategy is to survive until the 200 year pill is invented.
aroc91
not rated yet Jun 16, 2011
Now if we could just build to completion the experiment the Soviets did in the early sixties. The Soviets exploded a rocket in earth's atmosphere that contained several tons of water. The water remained liquid and was transparent to most radiation except UV rays, a huge cancer causer.


What's the relevance of this?

RealScience
not rated yet Jun 16, 2011
aroc91 - "210" seems to think that UV is a major cause of aging. But UV is mostly a cause of looking old (aging skin) rather than a cause of growing old (old body and mind), and he'd end up blocking the UV that we need to produce our vitamin D...
210
1 / 5 (1) Jun 16, 2011
aroc91 - "210" seems to think that UV is a major cause of aging. But UV is mostly a cause of looking old (aging skin) rather than a cause of growing old (old body and mind), and he'd end up blocking the UV that we need to produce our vitamin D...

Here, let's go here first: http://www.physor...343.html
And from that article, "...UV radiation is the most ubiquitous carcinogen (cancer-causing agent) for humans, in whom skin is the organ most commonly affected by cancer.."
Yes. YOU might get all of your Vitamin D from SKIN CANCER but, if you want to live a longer/longest possible life one should rid ones self of the biggest carcinogen of them all on the planet.
" But UV is mostly a cause of looking old (aging skin) rather than a cause of growing old..." OH NO! You can get skin cancer more than once and in many places at once. I assure you, you WILL NOT get old getting your vitamin D the way you seem to want to get it, there are several ways.
word-to-ya-muthas
RealScience
not rated yet Jun 16, 2011
210 - Although by number of cases skin cancer is the most common form of cancer, most skin cancers are easily curable so skin cancer's impact on life expectancy is fairly low. And vitamin D lowers rates of much deadlier cancers and a whole host of other nasty diseases.

Also skin cancer comes largely from sun burns where the skin peels. The peeling gets rid of the most damages cells, but the cells underneath, some of which have some damage, are forced to divide before DNA repairs can be completed.

In contrast vitamin D is best obtained without burning - a few minutes of sun at noon is enough. So get a bit of sun but not enough to burn, and you can have the best of both worlds.

If you are overly worried about UV, simply stay indoors or wear a hat rather than altering the whole planet's UV dose.
210
1 / 5 (1) Jun 17, 2011
210 - Although by number of cases skin cancer is the most common form of cancer, most skin cancers are easily curable so skin cancer's impact on life

The Sun is not the only source of D for the human body. We make very little Vitamin D during the fall and winter months. Enough is made in the summer and late spring. But with only the sun for D we would be crippled by age 55, especially women and dark skinned people.
The article was about prolonging life. IF we could remove the UV and gain a greater amount of D from diet, which most do in developed countries, fix the global food distribution methods; this means ending poverty too, and solve all our other longevity issues that I listed, we could add about 200 years to human life expectancy knowing what we know now. UV was not the only thing I wrote though its wide variations can cause a few problems, cancer being one and nothing to summarily dismiss. UV is also harmful to the eyes, not just skin
Telekinetic
1.7 / 5 (6) Jun 17, 2011
@ 210:
You're in the dark about sun exposure. The paranoia has gone overboard and it's been used as a scare tactic to sell sunscreen products. Any good alternative health site like Mercola.com has endorsed daily exposure to 20 minutes of sun for the best form of Vit. D3 your body manufactures, just to the point where your skin turns slightly pink. There are also benefits to UV exposure that aren't fully understood, but also contribute to cellular health. Some UV rays are harmful, while others are beneficial. I tell my 88 year old father to get his ass out into the sun for 15 minutes every day. It works.
210
1 / 5 (1) Jun 17, 2011
@ 210: slightly pink. There are also benefits to UV exposure that aren't fully understood, but also contribute to cellular health. Some UV rays are harmful, while others are beneficial. I tell my 88 year old father to get his ass out into the sun for 15 minutes every day. It works.

If there are benefits and they are NOT understood, how do you know they are 'benefits' or that they even exists? Your father is 88 years old...that means he has exceeded the life expectancy for his generation. Show him a little more respect why don't you?! He has in fact done something you may never do after all, dying is easy, living is the trick and living longer is what the article was about. During the course of a day one may get 20 minutes of sun without even thinking about it. It is a difficult thing to moderate, especially if one works outside. If you live further south than Atlanta Georgia then for nearly half a year you do not get enough sun to make enough D -just eat it!
RealScience
not rated yet Jun 17, 2011
210 - Unlike water-soluble B/C vitamins that your body needs daily, Vitamin D is a fat-soluble vitamin that your body can store for months. I make sure to get a good dose of sun in the fall, and then in March I find a place sheltered from the wind and start sunning again in spite of the snow all around.

My objection is not to getting vitamin D from food (which I do as a supplement in the winter), but to your wanting to geo-engineer our atmosphere to force all humans to get all of their vitamin D this way (and we are also not the only species on this planet).

Telekinetic is right that recent research has come out strongly in favor of moderate doses of sun being good for health.

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