title: Short-chain fatty acids induce gamma-globin gene expression by displacement of a HDAC3-NCoR repressor complex.
abstract: High-level induction of fetal (gamma) globin gene expression for therapy of beta-hemoglobinopathies likely requires local chromatin modification and dissociation of repressor complexes for gamma-globin promoter activation. A novel gamma-globin-inducing short-chain fatty acid derivative (SCFAD), RB7, which was identified through computational modeling, produced a 6-fold induction in a reporter assay that detects only strong inducers of the gamma-globin gene promoter and in cultured human erythroid progenitors. To elucidate the molecular mechanisms used by high-potency SCFADs, chromatin immunoprecipitation (ChIP) assays performed at the human gamma- and beta-globin gene promoters in GM979 cells and in erythroid progenitors demonstrate that RB7 and butyrate induce dissociation of HDAC3 (but not HDAC1 or HDAC2) and its adaptor protein NCoR, specifically from the gamma-globin gene promoter. A coincident and proportional recruitment of RNA polymerase II to the gamma-globin gene promoter was observed with exposure to these gamma-globin inducers. Knockdown of HDAC3 by siRNA induced transcription of the gamma-globin gene promoter, demonstrating that displacement of HDAC3 from the gamma-globin gene promoter by the SCFAD is sufficient to induce gamma-globin gene expression. These studies demonstrate new dynamic alterations in transcriptional regulatory complexes associated with SCFAD-induced activation of the gamma-globin gene and provide a specific molecular target for potential therapeutic intervention.
authors.affiliation: Gene Regulation Laboratories, Inc, Newton, MA, USA.
authors.forename: Rishikesh
authors.initials: R
authors.lastname: Mankidy
authors.forename: Douglas V
authors.initials: DV
authors.lastname: Faller
authors.forename: Rodwell
authors.initials: R
authors.lastname: Mabaera
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Lowrey
authors.forename: Michael S
authors.initials: MS
authors.lastname: Boosalis
authors.forename: Gary L
authors.initials: GL
authors.lastname: White
authors.forename: Serguei A
authors.initials: SA
authors.lastname: Castaneda
authors.forename: Susan P
authors.initials: SP
authors.lastname: Perrine
mesh_terms: D000328:Adult; D017931:DNA Primers; D005232:Fatty Acids, Volatile / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D005914:Globins / Q000187:drug effects / Q000235:genetics*; D006655:Histone Deacetylases / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D020014:K562 Cells; D009687:Nuclear Proteins / Q000187:drug effects / Q000235:genetics*; D056971:Nuclear Receptor Co-Repressor 1; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D012097:Repressor Proteins / Q000187:drug effects / Q000235:genetics*; D014162:Transfection; D000099186:Histone Deacetylase 3
chemical_list: D017931:DNA Primers; D005232:Fatty Acids, Volatile; D005914:Globins; D006655:Histone Deacetylases; D009687:Nuclear Proteins; D056971:Nuclear Receptor Co-Repressor 1; D012333:RNA, Messenger; D012097:Repressor Proteins; D000099186:Histone Deacetylase 3; C539127:NCOR1 protein, human