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PHYSIOLOGY
A protein named after the Greek goddess who spins life's thread has joined the short list of ways to extend a mouse's natural life span. Whereas lab mice can live about 2 years, mice engineered to overproduce this protein, called Klotho, have celebrated third birthdays, Makoto Kuro-o of the University of Texas Southwestern Medical Center in Dallas and his colleagues report online in this week's Science Express (www.sciencemag.org/cgi/content/ abstract/1112766). The mutant rodents represent a rare case of a single gene substantially influencing life span in mammals.
"I'm not a dreamer; I don't think we're going to find a master control gene for aging," says Harry Dietz, a geneticist at Johns Hopkins University in Baltimore, Maryland, who studies Klotho's counterpart in humans. But, he says, "this is the next best thing. We have found something that perhaps has the ability to make old age richer."
But Kuro-o, who discovered the gene that encodes Klotho, worries that "too much Klotho...