title: In vivo complex formation of PU.1 with HDAC1 associated with PU.1-mediated transcriptional repression.
abstract: We previously reported that overexpression of PU.1, a member of the Ets family of transcription factors, induces differentiation inhibition and apoptosis associated with c-Myc down-regulation in murine erythroleukemia (MEL) cells. To understand the molecular mechanism by which c-Myc is down-regulated due to overexpression of PU.1, we performed luciferase reporter assays using the mouse c-myc promoter. PU.1 repressed the activities of not only the c-myc promoter but also several other promoters. Experiments with deletion mutants of PU.1 revealed that the C-terminal region spanning amino acids (aa) 123-272 including the PEST and ETS domains but not the activation domain was sufficient for this transcriptional repression. It was unlikely that the repression was due to sequestration of a limited amount of CBP/p300 nor pCAF, because overexpression of these co-activators did not relieve PU.1-mediated transcriptional repression. Instead, it was found that the C-terminal aa 101-272 of PU.1 formed a complex with mSin3A and HDAC1 in vivo, which was speculated to be associated with the repression. The C-terminal region of PU.1 also formed a complex with the basic transcription factor TBP in vitro and in vivo. Our results suggest that overexpression of PU.1 induces transcriptional repression in several gene promoters including the c-myc promoter which may be mediated by its complex formation with HDACs.
authors.affiliation: Department of Cell Genetics, Sasaki Institute, 2-2, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan.
authors.forename: F
authors.initials: F
authors.lastname: Kihara-Negishi
authors.forename: H
authors.initials: H
authors.lastname: Yamamoto
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
authors.forename: T
authors.initials: T
authors.lastname: Yamada
authors.forename: T
authors.initials: T
authors.lastname: Sakurai
authors.forename: T
authors.initials: T
authors.lastname: Tamura
authors.forename: T
authors.initials: T
authors.lastname: Oikawa
mesh_terms: D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism; D015536:Down-Regulation; D017930:Genes, Reporter; D006367:HeLa Cells; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases / Q000378:metabolism*; D006801:Humans; D046911:Macromolecular Substances; D009154:Mutation; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D016271:Proto-Oncogene Proteins c-myc / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D012097:Repressor Proteins / Q000378:metabolism; D013539:Simian virus 40 / Q000235:genetics; D056264:Sin3 Histone Deacetylase and Corepressor Complex; D035181:TATA-Box Binding Protein; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D000099232:Proto-Oncogene Protein Spi-1
chemical_list: D004268:DNA-Binding Proteins; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases; D046911:Macromolecular Substances; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D012097:Repressor Proteins; D056264:Sin3 Histone Deacetylase and Corepressor Complex; D035181:TATA-Box Binding Protein; D015534:Trans-Activators; D014157:Transcription Factors; D000099232:Proto-Oncogene Protein Spi-1; C099683:SIN3A transcription factor; C110550:HDAC1 protein, human