Sir4 Deficiency Reverses Cell Senescence by Sub-Telomere Recombination.

Telomere shortening results in cellular senescence and the regulatory mechanisms remain unclear. Here, we report that the sub-telomere regions facilitate telomere lengthening by homologous recombination, thereby attenuating senescence in yeast Saccharomyces cerevisiae. The telomere protein complex Sir3/4 represses, whereas Rif1 promotes, the sub-telomere Y' element recombination. Genetic disruption of SIR4 ...
increases Y' element abundance and rescues telomere-shortening-induced senescence in a Rad51-dependent manner, indicating a sub-telomere regulatory switch in regulating organismal senescence by DNA recombination. Inhibition of the sub-telomere recombination requires Sir4 binding to perinuclear protein Mps3 for telomere perinuclear localization and transcriptional repression of the telomeric repeat-containing RNA TERRA. Furthermore, Sir4 repression of Y' element recombination is negatively regulated by Rif1 that mediates senescence-evasion induced by Sir4 deficiency. Thus, our results demonstrate a dual opposing control mechanism of sub-telomeric Y' element recombination by Sir3/4 and Rif1 in the regulation of telomere shortening and cell senescence.
Mesh Terms:
Cellular Senescence, Gene Deletion, Models, Biological, Recombination, Genetic, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Silent Information Regulator Proteins, Saccharomyces cerevisiae, Telomere, Telomere Homeostasis
Cells
Date: Dec. 01, 2020
Download Curated Data For This Publication
233997
Switch View:
  • Interactions 24