Gene Responsible For Aging Found In Yeast

Caloric restriction, which is the reduction of caloric intake without malnutrition, is a time proven method for extending the life span of mammals and postponing the manifestations of aging, including both functional decline and age-related diseases. Much is know about the physiological changes that occur in animals subjected to caloric restriction, but molecular mechanisms involved in this phenomenon are poorly understood because of the lack of workable experimental models.

"The efficacy of caloric restriction in retarding the aging process points to the importance of nutritional and metabolic mechanisms in aging," says Dr. Michal Jazwinski of the Louisiana State University. "If we could elucidate these mechanisms, it is likely that we would be able to develop relatively simple interventions that would alleviate the ravages of the aging process and improve quality of life in the later years in humans."

Dr. Jazwinski has developed the yeast Saccharomyces cerevisiae as an experimental model for the molecular analysis of the aging process. He has discovered that manipulating the nutritional intake of yeast cells can increase their life spans, providing a useful model for the molecular analysis of caloric restriction. Not only has Dr. Jazwinski shown that caloric restriction extends the life span of these cells but also postpones many of the physical manifestations of aging.

In a related study, Dr. Leonard Guarente of the Massachusetts Institute of Technology announced that his lab has identified a gene, SIR2, which regulates the life span of yeast. The gene is responsible for the production of a protein, Sir2, and the higher the level of this protein, the longer the life span of yeast cells. Sir2 is responsible for a process called genomic silencing that Dr. Guarente believes helps slow the aging process. However, it requires help of another compound, the level of which is determined by metabolic rate, to do this.

"Our findings thus provide a model for aging that is universal and explains how calorie restriction extends life span," says Dr. Guarente. "We believe that these studies could lead to the development of a drug that intervenes to strengthen the Sir2-silencing process and provides the benefits of calorie restriction without the extreme difficulty of the regimen itself."

###

This release is a summary of a presentation from the 100th General Meeting of the American Society for Microbiology, May 21-25, 2000, in Los Angeles. Additional information on these and other presentations at the 100th ASM General Meeting can be found online at http://www.asmusa.org/pcsrc/gm2000/presskit.htm or by contacting Jim Sliwa jsliwa@asmusa.org in the ASM Office of Communications.