UC San Francisco 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.
"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, PhD, 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."
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. Fertile roundworms with partially mutated, or "knocked out," daf-2 genes grow to be active, fertile adults that live more than twice as long as normal. And roundworms still in a larval stage of development, with more severely mutated genes, enter a state of extended prepubescence known as dauer diapause, in which larvae do not feed, are able to withstand harsh environmental conditions and live a long time.
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.'
The explanation, she said, appears to be that daf-2 acts in multiple groups of
signaling cells to control the production or activity of a second signal that
coordinates the growth and aging of ind
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Contact: Jennifer O'Brien
jobrien@itsa.ucsf.edu
415-476-1407
University of California - San Francisco
15-Oct-1998