PT  - JOURNAL ARTICLE
AU  - Taekyu Kang
AU  - Emily C. Moore
AU  - Emily E. K. Kopania
AU  - Christina D. King
AU  - Birgit Schilling
AU  - Judith Campisi
AU  - Jeffrey M. Good
AU  - Rachel B. Brem
TI  - A natural variation-based screen in mouse cells reveals USF2 as a regulator of the DNA damage response and cellular senescence
AID  - 10.1101/2022.04.21.489100
DP  - 2023 Jan 01
TA  - bioRxiv
PG  - 2022.04.21.489100
4099  - http://biorxiv.org/content/early/2023/01/23/2022.04.21.489100.short
4100  - http://biorxiv.org/content/early/2023/01/23/2022.04.21.489100.full
AB  - Cellular senescence is a program of cell cycle arrest, apoptosis resistance, and cytokine release induced by stress exposure in metazoan cells. Landmark studies in laboratory mice have characterized a number of master senescence regulators, including p16INK4a, p21, NF-kB, p53, and C/EBPβ. To discover other molecular players in senescence, we developed a screening approach to harness the evolutionary divergence between mouse species. We found that primary cells from the Mediterranean mouse Mus spretus, when treated with DNA damage to induce senescence, produced less cytokine and had less-active lysosomes than cells from laboratory M. musculus. We used allele-specific expression profiling to catalog senescence-dependent cis-regulatory variation between the species at thousands of genes. We then tested for correlation between these expression changes and interspecies sequence variants in the binding sites of transcription factors. Among the emergent candidate senescence regulators, we chose a little-studied cell cycle factor, USF2, for molecular validation. In acute irradiation experiments, cells lacking USF2 had compromised DNA damage repair and response. Longer-term senescent cultures without USF2 mounted an exaggerated senescence regulatory program—shutting down cell cycle and DNA repair pathways, and turning up cytokine expression, more avidly than wild-type. We interpret these findings under a model of pro-repair, anti-senescence regulatory function by USF2. Our study affords new insights into the mechanisms by which cells commit to senescence, and serves as a validated proof of concept for natural variation-based regulator screens.Competing Interest StatementThe authors have declared no competing interest.