Redistribution of silencing proteins from telomeres to the nucleolus is associated with extension of life span in S. cerevisiae.
Authors: Kennedy BK; Gotta M; Sinclair DA; Mills K; McNabb DS; Murthy M; Pak SM; Laroche T; Gasser SM; Guarente L Year: 1997 Journal: Cell Abstract: A prior genetic study indicated that activity of Sir silencing proteins at a hypothetical AGE locus is essential for long life span. In this model, the SIR4-42 mutation would direct the Sir protein complex to the AGE locus, giving rise to a long life span. We show by indirect immunofluorescence that Sir3p and Sir4p are redirected to the nucleolus in the SIR4-42 mutant. Furthermore, this relocalization is dependent on both UTH4 a novel yeast gene that extends life span, and its homologue YGL023. Strikingly, the Sir complex is relocalized from telomeres to the nucleolus in old wild-type cells. We propose that the rDNA is the AGE locus and that nucleolar function is compromised in old yeast cells in a way that may be mitigated by targeting of Sir proteins to the nucleolus. Reference
Integration:
Created on Nov. 5, 2012, 4:46 p.m. Not linked Integrated: False
Comment on This Data Unit