Preservation of lagging strand integrity at sites of stalled replication by Pol α-primase and 9-1-1 complex

Robin van Schendel; Ron Romeijn; Helena Buijs; Marcel Tijsterman

doi:10.1126/sciadv.abf2278

Preservation of lagging strand integrity at sites of stalled replication by Pol α-primase and 9-1-1 complex

Sci Adv. 2021 May 19;7(21):eabf2278. doi: 10.1126/sciadv.abf2278. Print 2021 May.

Authors

Robin van Schendel¹, Ron Romeijn¹, Helena Buijs¹, Marcel Tijsterman^{2

3}

Affiliations

¹ Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, Netherlands.
² Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, Netherlands. m.tijsterman@lumc.nl.
³ Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, Netherlands.

Abstract

During genome duplication, the replication fork encounters a plethora of obstacles in the form of damaged bases, DNA-cross-linked proteins, and secondary structures. How cells protect DNA integrity at sites of stalled replication is currently unknown. Here, by engineering "primase deserts" into the Caenorhabditis elegans genome close to replication-impeding G-quadruplexes, we show that de novo DNA synthesis downstream of the blocked fork suppresses DNA loss. We next identify the pol α-primase complex to limit deletion mutagenesis, a conclusion substantiated by whole-genome analysis of animals carrying mutated POLA2/DIV-1. We subsequently identify a new role for the 9-1-1 checkpoint clamp in protecting Okazaki fragments from resection by EXO1. Together, our results provide a mechanistic model for controlling the fate of replication intermediates at sites of stalled replication.

Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution License 4.0 (CC BY).