News from the molecular biology field is reinforcing the idea that "getting old" is more than just getting wrinkles and not understanding today's teenagers. A complicated system of many genes and proteins work together to gradually lead us all down the path to our later years.
One genetic aspect of aging is the gradual degradation of our teleomeres, repeating sequences of DNA that cap the ends of each chromosome. With each division of a cell, its telomeres become shorter and shorter -- until they are so short that the cell can no longer divide to reproduce or repair itself. Some cells that must divide often, including reproductive germ cells, produce an enzyme called telomerase that allows the cell to rebuild its telomeres, allowing continued division. Many cancer cells also produce telomerase, providing the cancer with its so-called "immortality."
A group made up of researchers at the University of Colorado, Massachusetts Institute of Technology, and a private company named Geron have located a gene that codes for key proteins in the telomerase enzyme. Finding this gene, they hope, may help them to protect telomeres in degrading cells -- or to shut off the reproductive immortality of cancerous cells.
In other genetics of aging news, a group at Massachusetts General Hospital has found that a muation to a gene in a species of roundworms, C. elegans, results in worms that live up to three times longer than normal. The mutant gene may slow down the organism's metabolism, switching the worm from fast burning of energy to storage of fat. In other studies, mice fed reduced-calorie diets also tend to live longer. Interestingly, the roundworm gene is 35% identical to a gene that produces insulin receptor sites in humans, raising the possibility that metabolism and aging may be linked in many animals -- perhaps even in humans.
In this hour of Science Friday, we'll take a look at the genetic basis of aging, and try to find out what we can do to slow down the sands of time.