title: FAD24 acts in concert with histone acetyltransferase HBO1 to promote adipogenesis by controlling DNA replication.
abstract: Preadipocytes differentiate into adipocytes through approximately two rounds of mitosis, referred to as mitotic clonal expansion (MCE), but the events early in the differentiation process are not fully understood. Previously, we identified and characterized a novel gene, fad24 (factor for adipocyte differentiation 24), induced to express at the early stages of adipocyte differentiation. Although fad24 clearly has crucial roles in adipogenesis, its precise functions remain unknown. Here we show that the knockdown of fad24 by RNAi in 3T3-L1 preadipocytes repressed MCE. Moreover, FAD24 interacts with HBO1, a histone acetyltransferase and positive regulator of DNA replication initiation. The knockdown of hbo1 repressed MCE and adipogenesis, indicating that FAD24 acts in concert with HBO1 to promote adipogenesis by controlling DNA replication. Regarding the molecular mechanisms behind the regulation of DNA replication by fad24, we revealed that FAD24 co-localizes with HBO1 to chromatin during late mitosis, which is when the prereplication initiation complex is assembled. Furthermore, chromatin immunoprecipitation experiments indicated that FAD24 localizes to origins of DNA replication with HBO1. When fad24 expression was inhibited during adipocyte differentiation, the recruitment of HBO1 to origins of DNA replication was reduced. Thus, FAD24 controls DNA replication by recruiting HBO1 to origins of DNA replication and is required for MCE during adipocyte differentiation.
authors.affiliation: Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Aichi 467-8603, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Johmura
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Osada
authors.forename: Makoto
authors.initials: M
authors.lastname: Nishizuka
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Imagawa
mesh_terms: D016475:3T3 Cells; D017667:Adipocytes / Q000166:cytology / Q000378:metabolism*; D050156:Adipogenesis / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D050976:Basic-Leucine Zipper Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D004261:DNA Replication / Q000187:drug effects / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D020868:Gene Silencing; D051548:Histone Acetyltransferases / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008938:Mitosis / Q000187:drug effects / Q000502:physiology*; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D051738:Origin Recognition Complex / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000494:pharmacology; D018741:Replication Origin / Q000502:physiology
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D018797:Cell Cycle Proteins; D002843:Chromatin; C502215:Noc3l protein, mouse; D009687:Nuclear Proteins; D051738:Origin Recognition Complex; D034741:RNA, Small Interfering; D051548:Histone Acetyltransferases; C525638:Kat7 protein, mouse