Science of Aging  

Brian K. Kennedy et al. Find that SIR4-42 Extends the Life Span of Yeast by 30% and May Play a Key Role in Regulating Aging

Who:Brian K. Kennedy, Nicanor R. Austriaco Jr., Jisi Zhang, Leonard Guarente
When:February 10, 1995
Methods: By culturing various strains of yeast under stressful conditions and analyzing the longest lived strains for key mutations
Institution: Massachusetts Institute of Technology
Where: Cambridge, Massachusetts, U.S.A
Technology: Incubator, Culture Plate, Microscope

In 1995 Brian Kennedy, Nicanor R. Austriaco Jr., Jisi Zhang, and Leonard Guarente found that the Silent Information Regulator(SIR) 4-42 plays a critical role in preventing aging of yeast.

They write:

Our findings suggest that sir4.42 extends life span by preventing recruitment of the SIR proteins to HM loci and telomeres, thereby increasing their concentration at other chromosomal regions.

The discovery came after Kennedy et al. cultured various strains of yeast and analyzed the genome of the longer lived strains.


  1. Kennedy, B., Austriaco, N., Zhang, J., and Guarente, L. (1995). Mutation in the silencing gene SIR4 can delay aging in Saccharomyces cerevisiae. Cell, 80, 485-496