The Yku70-Yku80 complex contributes to regulate double-strand break processing and checkpoint activation during the cell cycle.
DNA double-strand breaks (DSBs) are repaired by non-homologous end joining (NHEJ) or homologous recombination (HR). HR requires 5' DSB end degradation that occurs in the presence of cyclin-dependent kinase (CDK) activity. Here, we show that a lack of any of the NHEJ proteins Yku (Yku70-Yku80), Lif1 or DNA ligase IV (Dnl4) increases 5' DSB end degradation in G1 phase, with ykuDelta cells showing the strongest effect. This increase depends on MRX, the recruitment of which at DSBs is enhanced in ykuDelta G1 cells. DSB processing in G2 is not influenced by the absence of Yku, but it is delayed by Yku overproduction, which also decreases MRX loading on DSBs. Moreover, DSB resection in ykuDelta cells occurs independently of CDK activity, suggesting that it might be promoted by CDK-dependent inhibition of Yku.
Clerici
Michela
M
Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milan, Italy.
Mantiero
Davide
D
Guerini
Ilaria
I
Lucchini
Giovanna
G
Longhese
Maria Pia
MP
D015153:Blotting, Western; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology*; D047369:Chromatin Immunoprecipitation; D018844:Cyclin-Dependent Kinases / Q000235:genetics / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000235:genetics / Q000378:metabolism; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004706:Endodeoxyribonucleases / Q000235:genetics / Q000378:metabolism; D005090:Exodeoxyribonucleases / Q000235:genetics / Q000378:metabolism; D016193:G1 Phase / Q000235:genetics / Q000502:physiology; D016195:G2 Phase / Q000235:genetics / Q000502:physiology; D011995:Recombination, Genetic; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
D004268:DNA-Binding Proteins; C000607891:DNL4 protein, S cerevisiae; C114091:LIF1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C520769:YKU70 protein, S cerevisiae; C520770:YKU80 protein, S cerevisiae; D018844:Cyclin-Dependent Kinases; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; C094191:MRE11 protein, S cerevisiae; D011088:DNA Ligases; D000072481:DNA Ligase ATP