title: Hbo1 Links p53-dependent stress signaling to DNA replication licensing.
abstract: Hbo1 is a histone acetyltransferase (HAT) that is required for global histone H4 acetylation, steroid-dependent transcription, and chromatin loading of MCM2-7 during DNA replication licensing. It is the catalytic subunit of protein complexes that include ING and JADE proteins, growth regulatory factors and candidate tumor suppressors. These complexes are thought to act via tumor suppressor p53, but the molecular mechanisms and links between stress signaling and chromatin, are currently unknown. Here, we show that p53 physically interacts with Hbo1 and negatively regulates its HAT activity in vitro and in cells. Two physiological stresses that stabilize p53, hyperosmotic shock and DNA replication fork arrest, also inhibit Hbo1 HAT activity in a p53-dependent manner. Hyperosmotic stress during G(1) phase specifically inhibits the loading of the MCM2-7 complex, providing an example of the chromatin output of this pathway. These results reveal a direct regulatory connection between p53-responsive stress signaling and Hbo1-dependent chromatin pathways.
authors.affiliation: Department of Microbiology, University of Virginia Health System, P.O. Box 800734, Charlottesville, VA 22908-0734, USA.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Iizuka
authors.forename: Olga F
authors.initials: OF
authors.lastname: Sarmento
authors.forename: Takao
authors.initials: T
authors.lastname: Sekiya
authors.forename: Heidi
authors.initials: H
authors.lastname: Scrable
authors.forename: C David
authors.initials: CD
authors.lastname: Allis
authors.forename: M Mitchell
authors.initials: MM
authors.lastname: Smith
mesh_terms: D000818:Animals; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism; D002460:Cell Line; D004247:DNA / Q000235:genetics*; D004261:DNA Replication / Q000235:genetics*; D004789:Enzyme Activation; D051548:Histone Acetyltransferases / Q000235:genetics / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D009997:Osmotic Pressure; D011485:Protein Binding; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D018398:Homeodomain Proteins; C483230:ING4 protein, human; C508131:ING5 protein, human; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D004247:DNA; D051548:Histone Acetyltransferases; C496553:KAT7 protein, human; C525638:Kat7 protein, mouse