In vivo complex formation of PU.1 with HDAC1 associated with PU.1-mediated transcriptional repression

• Published in: Oncogene Vol. 20; no. 42; pp. 6039 - 6047
• Main Authors: KIHARA-NEGISHI, Fumiko, YAMAMOTO, Hitomi, SUZUKI, Mitsuhiro, YAMADA, Toshiyuki, SAKURAI, Takuya, TAMURA, Takaaki, OIKAWA, Tsuneyuki
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing 20.09.2001; Nature Publishing Group
• Subjects: Amino acids; Apoptosis; Biological and medical sciences; Biotechnology; c-myc gene; c-Myc protein; CBP protein; Cell Line; Deletion mutant; DNA-Binding Proteins - metabolism; Down-Regulation; Erythroleukemia; ETS protein; Fundamental and applied biological sciences. Psychology; Gene deletion; Gene silencing; Gene therapy; Genes; Genes, Reporter; HDAC1 protein; Health. Pharmaceutical industry; HeLa Cells; Histone Deacetylase 1; Histone Deacetylases - metabolism; Humans; Industrial applications and implications. Economical aspects; Kinases; Macromolecular Substances; mSin3A; Mutation; Myc protein; p300 protein; Promoter Regions, Genetic; Promoters; Protein Structure, Tertiary; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins - metabolism; Proto-Oncogene Proteins - physiology; Proto-Oncogene Proteins c-myc - biosynthesis; Proto-Oncogene Proteins c-myc - genetics; PU.1 protein; Repressor Proteins - metabolism; RNA, Messenger - biosynthesis; Simian virus 40 - genetics; TATA-Box Binding Protein; TBP protein; Trans-Activators - genetics; Trans-Activators - metabolism; Trans-Activators - physiology; Transcription factors; Transcription Factors - metabolism; Transcription, Genetic; In vivo; Association; Repression; Transcription
• DOI: 10.1038/sj.onc.1204756
• ISSN: 0950-9232

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.