Crocs Uncover

Bizarre Species

martes, 9 de junio de 2009

Somatic cells

The Secret to Roundworm Longevity: Sex Cells

The cells of especially long-lived roundworms run some of the same genetic programs found in sperm and egg cells. Known as germline cells, they can replicate indefinitely without wearing down, and have fascinated researchers seeking lessons in their longevity.

Other, so-called somatic cells rapidly accumulate genetic and mechanical damage, and divide roughly 50 times before dying.

Exactly why germline cells live so long isn’t completely understood. They do possess unusually large telomeres — protein caps on the ends of chromosomes that prevent those genetic spools from unraveling. They also possess mutations in genes linked to fighting off pathogens and repairing toxin damage.

In a study described Sunday in Nature, researchers compared gene expression in germline cells with somatic cells taken from roundworms engineered to live several times longer than normal. The profiles matched. When long-lived and standard roundworms were exposed to pollutants, cells from the former escaped relatively unscathed. And when the researchers turned those typically-germline genes off, the worms’ lifespans returned to normal.

Whether the same mechanisms work in humans remains to be seen, but the prospect is tantalizing.

“Given that protection of the germ line is an evolutionarily shared trait across species, it will be interesting to investigate whether this is a broadly conserved mechanism of modulating lifespan,” wrote the researchers.

If so, then those mutations could be used in therapies that “assist in cellular repair and possibly regeneration,” they wrote.

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