Human SNM1A and XPF–ERCC1 collaborate to initiate DNA interstrand cross-link repair

Anderson T. Wang; Blanka Sengerová; Emma Cattell; Takabumi Inagawa; Janet M. Hartley; Konstantinos Kiakos; Nicola A. Burgess-Brown; Lonnie P. Swift; Jacqueline H. Enzlin; Christopher J. Schofield; Opher Gileadi; John A. Hartley; Peter J. McHugh

doi:10.1101/gad.15699211

Human SNM1A and XPF–ERCC1 collaborate to initiate DNA interstrand cross-link repair

¹Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom;
²Cancer Research UK Drug–DNA Interactions Research Group, UCL Cancer Institute, University College London, London WC1E 6BT, United Kingdom;
³Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom;
⁴Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, United Kingdom

↵5 Present address: Department of Cell Biology and Genetics, Erasmus Medical Center, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands.

Abstract

One of the major DNA interstrand cross-link (ICL) repair pathways in mammalian cells is coupled to replication, but the mechanistic roles of the critical factors involved remain largely elusive. Here, we show that purified human SNM1A (hSNM1A), which exhibits a 5′–3′ exonuclease activity, can load from a single DNA nick and digest past an ICL on its substrate strand. hSNM1A-depleted cells are ICL-sensitive and accumulate replication-associated DNA double-strand breaks (DSBs), akin to ERCC1-depleted cells. These DSBs are Mus81-induced, indicating that replication fork cleavage by Mus81 results from the failure of the hSNM1A- and XPF–ERCC1-dependent ICL repair pathway. Our results reveal how collaboration between hSNM1A and XPF–ERCC1 is necessary to initiate ICL repair in replicating human cells.