CLONING AND CHARACTERIZATION OF LAG1, A LONGEVITY-ASSURANCE GENE IN YEAST

The yeast Saccharomyces cerevisiae has a finite life span that is meas ured by the number of times the individual cell divides. The gene codi ng for one of several transcripts that are differentially expressed du ring the replicative life span has been cloned. The nucleotide sequenc e revealed an open reading frame capable of encoding a transmembrane p rotein of 411 amino acids that displays no significant similarities to any known proteins. Nevertheless, sequences similar to this gene were found in several mammals, including humans. The transcript levels dec reased with replicative age of yeast cells. A gene deletion in haploid eels resulted in a pronounced increase (approximately 50%) in mean an d in maximum life span. These results indicate that this gene, which w e call LAG1, plays a role in determining yeast longevity.