The 9-1-1 checkpoint clamp coordinates resection at DNA double strand breaks.
DNA-end resection, the generation of single-stranded DNA at DNA double strand break (DSB) ends, is critical for controlling the many cellular responses to breaks. Here we show that the conserved DNA damage checkpoint sliding clamp (the 9-1-1 complex) plays two opposing roles coordinating DSB resection in budding yeast. We show that the major effect of 9-1-1 is to inhibit resection by promoting the recruitment of Rad9(53BP1) near DSBs. However, 9-1-1 also stimulates resection by Exo1- and Dna2-Sgs1-dependent nuclease/helicase activities, and this can be observed in the absence of Rad9(53BP1). Our new data resolve the controversy in the literature about the effect of the 9-1-1 complex on DSB resection. Interestingly, the inhibitory role of 9-1-1 on resection is not observed near uncapped telomeres because less Rad9(53BP1) is recruited near uncapped telomeres. Thus, 9-1-1 both stimulates and inhibits resection and the effects of 9-1-1 are modulated by different regions of the genome. Our experiments illustrate the central role of the 9-1-1 checkpoint sliding clamp in the DNA damage response network that coordinates the response to broken DNA ends. Our results have implications in all eukaryotic cells.
Institute for Cell and Molecular Biosciences (ICaMB), Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
Greg H P
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Institute for Cell and Molecular Biosciences (ICaMB), Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK d.a.lydall@ncl.ac.uk.
David
D
Lydall
D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D053903:DNA Breaks, Double-Stranded; D004265:DNA Helicases / Q000378:metabolism; D004260:DNA Repair; D004271:DNA, Fungal / Q000378:metabolism; D005090:Exodeoxyribonucleases / Q000378:metabolism; D017353:Gene Deletion; D011485:Protein Binding; D053484:RecQ Helicases / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D016615:Telomere / Q000378:metabolism
D018797:Cell Cycle Proteins; D004271:DNA, Fungal; C099938:MEC3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C069930:rad9 protein; D005090:Exodeoxyribonucleases; C028450:exodeoxyribonuclease I; C090472:SGS1 protein, S cerevisiae; D004265:DNA Helicases; C410222:DNA2 protein, S cerevisiae; D053484:RecQ Helicases