The ubiquitin ligase RFWD3 is required for translesion DNA synthesis

  • Mol Cell. 2021 Feb 4;81(3):442-458.e9. doi: 10.1016/j.molcel.2020.11.029.
Irene Gallina  1 ,  Ivo A Hendriks  1 ,  Saskia Hoffmann  1 ,  Nicolai B Larsen  1 ,  Joachim Johansen  1 ,  Camilla S Colding-Christensen  1 ,  Lisa Schubert  1 ,  Selene Sellés-Baiget  1 ,  Zita Fábián  1 ,  Ulrike Kühbacher  1 ,  Alan O Gao  1 ,  Markus Räschle  2 ,  Simon Rasmussen  1 ,  Michael L Nielsen  1 ,  Niels Mailand  1 ,  Julien P Duxin  3
Affiliations
  • 1. The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.
  • 2. Department of Molecular Biotechnology and Systems Biology, Technical University of Kaiserslautern, 67653 Kaiserslautern, Germany.
  • 3. The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark. Electronic address: [email protected].
PMID: 33321094 DOI: 10.1016/j.molcel.2020.11.029
Abstract

Lesions on DNA uncouple DNA synthesis from the replisome, generating stretches of unreplicated single-stranded DNA (ssDNA) behind the replication fork. These ssDNA gaps need to be filled in to complete DNA duplication. Gap-filling synthesis involves either translesion DNA synthesis (TLS) or template switching (TS). Controlling these processes, ubiquitylated PCNA recruits many proteins that dictate pathway choice, but the Enzymes regulating PCNA ubiquitylation in vertebrates remain poorly defined. Here we report that the E3 ubiquitin Ligase RFWD3 promotes ubiquitylation of proteins on ssDNA. The absence of RFWD3 leads to a profound defect in recruitment of key repair and signaling factors to damaged chromatin. As a result, PCNA ubiquitylation is inhibited without RFWD3, and TLS across different DNA lesions is drastically impaired. We propose that RFWD3 is an essential coordinator of the response to ssDNA gaps, where it promotes ubiquitylation to drive recruitment of effectors of PCNA ubiquitylation and DNA damage bypass.

Keywords
CHROMASS; DPC repair; HMCES; ICL repair; PCNA; RFWD3; TLS; UV lesions; anemia; ubiquitylation.