Timing of DNA damage checkpoint adaptation predicts post-mitotic proliferative competence

Abstract Persistent DNA damage creates a conflict between checkpoint-enforced arrest and continued proliferation. Although adaptation enables cells to escape this arrest, checkpoint bypass does not ensure renewed proliferation. Here, we show that the duration of checkpoint-associated metaphase arrest predicts proliferative re-entry after telomere dysfunction in budding yeast. Using population-level analyses and single-cell live imaging, we resolved adaptation into checkpoint attenuation, anaphase entry, mitotic completion and renewed proliferation. These transitions were separable: cells could enter anaphase yet fail to resume proliferation. Among cells that bypassed the checkpoint, each additional 100 min of metaphase arrest was associated with an 80% reduction in the odds of complete proliferative re-entry. This inverse relationship was reproducible across independent experiments and persisted across changes in spindle assembly checkpoint activity, the severity of telomere dysfunction and DNA-end metabolism, despite context-dependent shifts in arrest timing and overall proliferative competence. Comparisons across damage contexts and checkpoint states further showed that the predictive value of metaphase duration depends on the trajectory in which arrest develops. Thus, checkpoint bypass and productive proliferation are separable outcomes, with arrest duration providing a context-dependent predictor of proliferative competence after adaptation.