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1st appeared 19 October 1998 Finding Offers Insight into Way Genes Regulate Aging and Life Span UCSF researchers have made a significant finding in roundworms that may offer insight into the way in which genes regulate aging and life span in humans. In a study published in the October 16 issue of Cell, they report that a gene already known to play an important role in controlling aging in roundworms does so not by acting within individual cells to control each cell's fate, but by acting within certain cells to coordinate the aging process of the whole organism.
The researchers conducted their study on a gene known as daf-2, which Kenyon's lab had previously determined plays a significant role in controlling the aging process and life span of the roundworm known as nematode C. elegans. What the researchers have now discovered is that if the level of daf-2 activity is lowered in just a small group of cells, the life span of the whole animal is extended. "Somehow," said Kenyon, "this small group of cells allows all the cells in the animal to live longer -- even those that contain the normal gene." As many biological processes are known to be conserved between C. elegans and vertebrates, the finding offers possible insight into the way that human aging is controlled. The possibility is particularly tantalizing because of several apparent similarities in the response of C. elegans and rats and mice -- a step closer to humans -- to low-calorie diets. As with C. elegans, when rats and mice are fed low calorie diets they live longer than normal, and the first response they have on the molecular level is a drop in insulin levels. The equivalent of the daf-2 gene in humans produces the cell receptor for insulin and insulin-like growth factor (IGF), which plays a role in regulating food metabolism. And, just as in C. elegans, the human insulin receptor acts in signaling cells, amongst other places, prompting second signals that then effect the behavior of other cells. "It may be that the signaling cascade prompted by daf-2 in certain cells occurs in a similar way in the insulin/IGF family of receptors in mammals in response to caloric restriction," said Kenyon. If this is the case, she said, it may be that the hormone signaling pathway in C. elegans hints at a similar process regulating aging in humans. "It may be that one portion of this pathway is involved in the control of aging, so the challenge is to figure out which portion that is." Links: Scientists Describe Gene That Controls Life Span Source: Jennifer O'Brien, News Services |
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"Our study
indicates there is a mechanism that causes all of the
cells in the animal to reach a consensus," said the
senior author of the study, Cynthia Kenyon, the Herbert
Boyer Professor of Biochemistry and Biophysics at UCSF.
"And that mechanism appears to be sparked into
action by particular genes acting within certain types of
cells."