title: Yeast G1 DNA damage checkpoint regulation by H2A phosphorylation is independent of chromatin remodeling.
abstract: Recent studies of yeast G1 DNA damage response have identified characteristic changes in chromatin adjacent to double-strand breaks (DSBs). Histone H2A (yeast H2AX) is rapidly phosphorylated on S129 by the kinase Tel1 (ATM) over a domain extending kilobases from the DSB. The adaptor protein Rad9 (53BP1) is recruited to this chromatin domain through binding of its tudor domains to histone H3 diMe-K79. Multisite phosphorylation of Rad9 by Mec1 (ATR) then activates the signaling kinase Rad53 (CHK2) to induce a delay in G1. Here, we report a previously undescribed role for Tel1 in G1 checkpoint response and show that H2A is the likely phosphorylation target, in a much as S129 mutation to Ala confers defects in G1 checkpoint arrest, Rad9 phosphorylation, and Rad53 activation. Importantly, Rad9 fails to bind chromatin adjacent to DSBs in H2A-S129A mutants. Previous work showed that H2A phosphorylation allows binding of NuA4, SWR, and INO80 chromatin remodeling complexes, perhaps exposing H3 diMe-K79. Yet, mutants lacking SWR or INO80 remain checkpoint competent, whereas loss of NuA4-dependent histone acetylation leads to G1 checkpoint persistence, suggesting that H2A phosphorylation promotes two independent events, rapid Rad9 recruitment to DSBs and subsequent remodeling by NuA4, SWR, and INO80.
authors.affiliation: Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Javaheri
authors.forename: Robert
authors.initials: R
authors.lastname: Wysocki
authors.forename: Olivier
authors.initials: O
authors.lastname: Jobin-Robitaille
authors.forename: Mohammed
authors.initials: M
authors.lastname: Altaf
authors.forename: Jacques
authors.initials: J
authors.lastname: Côté
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Kron
mesh_terms: D000123:Acetyltransferases / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism; D064447:Checkpoint Kinase 2; D042002:Chromatin Assembly and Disassembly / Q000235:genetics; D004249:DNA Damage; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology*; D016193:G1 Phase / Q000235:genetics*; D051548:Histone Acetyltransferases; D006657:Histones / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D009154:Mutation; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D006657:Histones; C483404:INO80 complex, S cerevisiae; D047908:Intracellular Signaling Peptides and Proteins; D029701:Saccharomyces cerevisiae Proteins; C069930:rad9 protein; D000123:Acetyltransferases; D051548:Histone Acetyltransferases; C504740:NuA4 protein, S cerevisiae; D064447:Checkpoint Kinase 2; D017346:Protein Serine-Threonine Kinases; C513623:TEL1 protein, S cerevisiae; C067022:RAD53 protein, S cerevisiae