DREAM repressive activity links somatic mutation, lifespan and disease.

The DREAM complex has emerged as a central repressor of DNA repair, raising questions as to whether such repression exerts long-term effects on human health. Here we establish that DREAM-associated activity significantly impacts lifetime somatic mutation burden, and that such effects are linked to altered lifespan and age-related disease pathology. First, joint profiling of DREAM-associated activity (quantified from the expression of genes transcriptionally repressed by DREAM) and somatic mutations across a single-cell atlas of 21 mouse tissues shows that cellular niches with lower DREAM-associated activity have decreased mutation rates. Second, DREAM-associated activity predicts the varied lifespans observed across 92 mammals, with low activity marking longer-lived species. Third, reduced DREAM-associated activity in individuals with Alzheimer's disease predicts late disease onset and decreased risk for severe neuropathology. Finally, DREAM knockout in mice protects against mutation accumulation, reducing single-base substitutions by 4.2% and insertion/deletions by 19.6% in the brain. These findings position DREAM as a key regulator of aging.