Histone H3 Thr 45 phosphorylation is a replication-associated post-translational modification in S. cerevisiae.
Post-translational histone modifications are crucial for the regulation of numerous DNA-templated processes, and are thought to mediate both alteration of chromatin dynamics and recruitment of effector proteins to specific regions of the genome. In particular, histone Ser/Thr phosphorylation regulates multiple nuclear functions in the budding yeast Saccharomyces cerevisiae, including transcription, DNA damage repair, mitosis, apoptosis and sporulation. Although modifications to chromatin during replication remain poorly understood, a number of recent studies have described acetylation of the histone H3 N-terminal alpha-helix (alphaN helix) at Lys 56 as a modification that is important for maintenance of genomic integrity during DNA replication and repair. Here, we report phosphorylation of H3 Thr 45 (H3-T45), a histone modification also located within the H3 alphaN helix in S. cerevisiae. Thr 45 phosphorylation peaks during DNA replication, and is mediated by the S phase kinase Cdc7-Dbf4 as part of a multiprotein complex identified in this study. Furthermore, loss of phosphorylated H3-T45 causes phenotypes consistent with replicative defects, and prolonged replication stress results in H3-T45 phosphorylation accumulation over time. Notably, the phenotypes described here are independent of Lys 56 acetylation status, and combinatorial mutations to both Thr 45 and Lys 56 of H3 cause synthetic growth defects. Together, these data identify and characterize H3-T45 phosphorylation as a replication-associated histone modification in budding yeast.
Baker
Stephen P
SP
Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
Phillips
Jennifer
J
Anderson
Scott
S
Qiu
Qifeng
Q
Shabanowitz
Jeffrey
J
Smith
M Mitchell
MM
Yates
John R
JR
Hunt
Donald F
DF
Grant
Patrick A
PA
D000107:Acetylation; D019943:Amino Acid Substitution / Q000502:physiology; D002166:Camptothecin / Q000493:pharmacokinetics; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D049109:Cell Proliferation; D004261:DNA Replication / Q000187:drug effects / Q000502:physiology*; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D006918:Hydroxyurea / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D008239:Lysine / Q000378:metabolism; D009154:Mutation / Q000502:physiology; D015739:Nocodazole / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D011499:Protein Processing, Post-Translational / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016196:S Phase / Q000187:drug effects / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D013912:Threonine / Q000378:metabolism*
D018797:Cell Cycle Proteins; C088096:Dbf4 protein, S cerevisiae; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; C069200:MCM5 protein, S cerevisiae; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D013912:Threonine; C489404:CDC7 protein, S cerevisiae; C088937:MEC1 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; C513623:TEL1 protein, S cerevisiae; D008239:Lysine; D015739:Nocodazole; D006918:Hydroxyurea; D002166:Camptothecin