TY - JOUR T1 - The HMCES DNA-protein cross-link functions as a constitutive DNA repair intermediate JF - bioRxiv DO - 10.1101/2021.07.29.454365 SP - 2021.07.29.454365 AU - Daniel R. Semlow AU - Victoria A. MacKrell AU - Johannes C. Walter Y1 - 2021/01/01 UR - http://biorxiv.org/content/early/2021/07/29/2021.07.29.454365.abstract N2 - The HMCES protein forms a covalent DNA-protein cross-link (DPC) with abasic (AP) sites in ssDNA, and the resulting HMCES-DPC is thought to suppress double-strand break formation in S phase. However, the dynamics of HMCES cross-linking and whether any DNA repair pathways normally include an HMCES-DPC intermediate remain unknown. Here, we show that an HMCES-DPC forms efficiently on the AP site generated during replication-coupled DNA interstrand cross-link (ICL) repair. We use this system to show that HMCES cross-links form on DNA after the replicative CMG helicase has passed over the AP site, and that HMCES is subsequently removed by the SPRTN protease. The HMCES-DPC suppresses DSB formation, slows translesion synthesis (TLS) past the AP site, and introduces a bias for insertion of deoxyguanosine opposite the AP site. These data show that HMCES-DPCs can form as constitutive intermediates in replication-coupled repair, and they suggest a general model of how HMCES protects AP sites during DNA replication.Competing Interest StatementThe authors have declared no competing interest. ER -