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Disease-associated DNA2 nuclease–helicase protects cells from lethal chromosome under-replication
journal contribution
posted on 2023-06-07, 07:18 authored by Benoît Falquet, Gizem Ölmezer, Franz Enkner, Dominique Klein, Kiran Challa, Rowin AppanahRowin Appanah, Susan M Gasser, Ulrich RassUlrich RassDNA2 is an essential nuclease–helicase implicated in DNA repair, lagging-strand DNA synthesis, and the recovery of stalled DNA replication forks (RFs). In Saccharomyces cerevisiae, dna2? inviability is reversed by deletion of the conserved helicase PIF1 and/or DNA damage checkpoint-mediator RAD9. It has been suggested that Pif1 drives the formation of long 5'-flaps during Okazaki fragment maturation, and that the essential function of Dna2 is to remove these intermediates. In the absence of Dna2, 5'-flaps are thought to accumulate on the lagging strand, resulting in DNA damage-checkpoint arrest and cell death. In line with Dna2’s role in RF recovery, we find that the loss of Dna2 results in severe chromosome under-replication downstream of endogenous and exogenous RF-stalling. Importantly, unfaithful chromosome replication in Dna2-mutant cells is exacerbated by Pif1, which triggers the DNA damage checkpoint along a pathway involving Pif1’s ability to promote homologous recombination-coupled replication. We propose that Dna2 fulfils its essential function by promoting RF recovery, facilitating replication completion while suppressing excessive RF restart by recombination-dependent replication (RDR) and checkpoint activation. The critical nature of Dna2’s role in controlling the fate of stalled RFs provides a framework to rationalize the involvement of DNA2 in Seckel syndrome and cancer.
Funding
Swiss National Science Foundation; 31003A_176286
Novartis Research Foundation
History
Publication status
- Published
File Version
- Published version
Journal
Nucleic Acids ResearchISSN
1362-4962Publisher
Oxford JournalsExternal DOI
Issue
13Volume
48Page range
7265-7278Department affiliated with
- Sussex Centre for Genome Damage Stability Publications
Research groups affiliated with
- Genome Damage and Stability Centre Publications
Full text available
- Yes
Peer reviewed?
- Yes