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The 9-1-1 checkpoint clamp stimulates DNA resection by Dna2-Sgs1 and Exo1

Lookup NU author(s): Dr Greg Ngo, Dr Marion Dubarry, Professor David Lydall



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Single-stranded DNA (ssDNA) at DNA ends is an important regulator of the DNA damage response. Resection, the generation of ssDNA, affects DNA damage checkpoint activation, DNA repair pathway choice, ssDNA-associated mutation and replication fork stability. In eukaryotes, extensive DNA resection requires the nuclease Exo1 and nuclease/helicase pair: Dna2 and Sgs1(BLM). How Exo1 and Dna2-Sgs1(BLM) coordinate during resection remains poorly understood. The DNA damage checkpoint clamp (the 9-1-1 complex) has been reported to play an important role in stimulating resection but the exact mechanism remains unclear. Here we show that the human 9-1-1 complex enhances the cleavage of DNA by both DNA2 and EXO1 in vitro, showing that the resection-stimulatory role of the 9-1-1 complex is direct. We also show that in Saccharomyces cerevisiae, the 9-1-1 complex promotes both Dna2-Sgs1 and Exo1-dependent resection in response to uncapped telomeres. Our results suggest that the 9-1-1 complex facilitates resection by recruiting both Dna2-Sgs1 and Exo1 to sites of resection. This activity of the 9-1-1 complex in supporting resection is strongly inhibited by the checkpoint adaptor Rad9(53BP1). Our results provide important mechanistic insights into how DNA resection is regulated by checkpoint proteins and have implications for genome stability in eukaryotes.

Publication metadata

Author(s): Ngo GHP, Balakrishnan L, Dubarry M, Campbell JL, Lydall D

Publication type: Article

Publication status: Published

Journal: Nucleic Acids Research

Year: 2014

Volume: 42

Issue: 16

Pages: 10516-10528

Print publication date: 15/09/2014

Online publication date: 13/08/2014

Acceptance date: 01/08/2014

Date deposited: 02/07/2015

ISSN (print): 0305-1048

ISSN (electronic): 1362-4962

Publisher: Oxford University Press


DOI: 10.1093/nar/gku746


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Funder referenceFunder name
075294Wellcome Trust
093088Wellcome Trust
EMBO ALTF218-2012European Molecular Biology Organization
GM098328National Institutes of Health
GM100186National Institutes of Health
093088/Z/10/ZWellcome Trust