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Updated: Aug 16, 2026

A Suppressor Screen for the Characterization of Genetic Links Regulating Chronological Lifespan in Saccharomyces cerevisiae
Published on: September 17, 2020
Mammalian SIRT1 limits replicative life span in response to chronic genotoxic stress
Katrin F Chua1, Raul Mostoslavsky, David B Lombard
1Howard Hughes Medical Institute, Children's Hospital, CBR Institute for Biomedical Research, Department of Genetics, Harvard University Medical School, Boston, MA 02115, USA.
Abstract:
The Saccharomyces cerevisiae chromatin silencing factor Sir2 suppresses genomic instability and extends replicative life span. In contrast, we find that mouse embryonic fibroblasts (MEFs) deficient for SIRT1, a mammalian Sir2 homolog, have dramatically increased resistance to replicative senescence. Extended replicative life span of SIRT1-deficient MEFs correlates with enhanced proliferative capacity under conditions of chronic, sublethal oxidative stress. In this context, SIRT1-deficient cells fail to normally upregulate either the p19(ARF) senescence regulator or its downstream target p53. However, upon acute DNA damage or oncogene expression, SIRT1-deficient cells show normal p19(ARF) induction and cell cycle arrest. Together, our findings demonstrate an unexpected SIRT1 function in promoting replicative senescence in response to chronic cellular stress and implicate p19(ARF) as a downstream effector in this pathway.
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