Histone H2A phosphorylation controls Crb2 recruitment at DNA breaks, maintains checkpoint arrest, and influences DNA repair in fission yeast.
Mammalian ATR and ATM checkpoint kinases modulate chromatin structures near DNA breaks by phosphorylating a serine residue in the carboxy-terminal tail SQE motif of histone H2AX. Histone H2A is similarly regulated in Saccharomyces cerevisiae. The phosphorylated forms of H2AX and H2A, known as gamma-H2AX and gamma-H2A, are thought to be important for DNA repair, although their evolutionarily conserved roles are unknown. Here, we investigate gamma-H2A in the fission yeast Schizosaccharomyces pombe. We show that formation of gamma-H2A redundantly requires the ATR/ATM-related kinases Rad3 and Tel1. Mutation of the SQE motif to AQE (H2A-AQE) in the two histone H2A genes caused sensitivity to a wide range of genotoxic agents, increased spontaneous DNA damage, and impaired checkpoint maintenance. The H2A-AQE mutations displayed a striking synergistic interaction with rad22Delta (Rad52 homolog) in ionizing radiation (IR) survival. These phenotypes correlated with defective phosphorylation of the checkpoint proteins Crb2 and Chk1 and a failure to recruit large amounts of Crb2 to damaged DNA. Surprisingly, the H2A-AQE mutations substantially suppressed the IR hypersensitivity of crb2Delta cells by a mechanism that required the RecQ-like DNA helicase Rqh1. We propose that gamma-H2A modulates checkpoint and DNA repair through large-scale recruitment of Crb2 to damaged DNA. This function correlates with evidence that gamma-H2AX regulates recruitment of several BRCA1 carboxyl terminus domain-containing proteins (NBS1, 53BP1, MDC1/NFBD1, and BRCA1) in mammals.
Nakamura
Toru M
TM
Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA. nakamut@scripps.edu
Du
Li-Lin
LL
Redon
Christophe
C
Russell
Paul
P
D000595:Amino Acid Sequence; D000818:Animals; D002453:Cell Cycle / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D064447:Checkpoint Kinase 2; D004249:DNA Damage; D004265:DNA Helicases / Q000378:metabolism; D004260:DNA Repair; D004843:Epistasis, Genetic; D005656:Fungal Proteins / Q000378:metabolism; D042822:Genomic Instability; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism*; D016415:Sequence Alignment
D018797:Cell Cycle Proteins; C109867:Crb2 protein, S pombe; D005656:Fungal Proteins; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D011494:Protein Kinases; D064447:Checkpoint Kinase 2; D017346:Protein Serine-Threonine Kinases; C513623:TEL1 protein, S cerevisiae; C456840:rad3 protein, S pombe; C513624:tel1 protein, S pombe; D004265:DNA Helicases; C106462:Rqh1 protein, S pombe