MEC1-dependent redistribution of the Sir3 silencing protein from telomeres to DNA double-strand breaks.
Level 5 - mechanism / opinion, no new human data
Preclinical bench laboratory study in yeast without human data
PubMed 10367890 · doi:10.1016/s0092-8674(00)80772-2
What was done
The authors investigated the localization and repair role of the yeast Sir3 silencing protein following DNA double-strand breaks (DSBs), evaluating cell cycle specificity and requirement for checkpoint genes MEC1 and RAD9.
What was found
The abstract reports no numerical data. Qualitatively, Sir3p was released from telomeres upon induction of DSBs, bound to break sites, and mediated repair independently of mating type. Relocalization occurred specifically during S phase and required MEC1 and RAD9.
Why it matters
It describes a mechanism whereby preformed chromatin-silencing machinery is mobilized by DNA damage checkpoint sensors homologous to human ATM to repair double-strand breaks.
Limits
The work was conducted exclusively in a yeast model, meaning conservation in human cells remains unproven in this report. No quantitative measures, sample sizes, or statistical estimates are provided in the abstract.
Cited by
- supports Chromosomal breaks recruit sirtuins away from gene regulation to perform DNA repair, contributing to aging in yeast.