title: The histone chaperone Spt6 coordinates histone H3K27 demethylation and myogenesis.
abstract: Histone chaperones affect chromatin structure and gene expression through interaction with histones and RNA polymerase II (PolII). Here, we report that the histone chaperone Spt6 counteracts H3K27me3, an epigenetic mark deposited by the Polycomb Repressive Complex 2 (PRC2) and associated with transcriptional repression. By regulating proper engagement and function of the H3K27 demethylase KDM6A (UTX), Spt6 effectively promotes H3K27 demethylation, muscle gene expression, and cell differentiation. ChIP-Seq experiments reveal an extensive genome-wide overlap of Spt6, PolII, and KDM6A at transcribed regions that are devoid of H3K27me3. Mammalian cells and zebrafish embryos with reduced Spt6 display increased H3K27me3 and diminished expression of the master regulator MyoD, resulting in myogenic differentiation defects. As a confirmation for an antagonistic relationship between Spt6 and H3K27me3, inhibition of PRC2 permits MyoD re-expression in myogenic cells with reduced Spt6. Our data indicate that, through cooperation with PolII and KDM6A, Spt6 orchestrates removal of H3K27me3, thus controlling developmental gene expression and cell differentiation.
authors.affiliation: Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: A Hongjun
authors.initials: AH
authors.lastname: Wang
authors.forename: Hossein
authors.initials: H
authors.lastname: Zare
authors.forename: Kambiz
authors.initials: K
authors.lastname: Mousavi
authors.forename: Chaochen
authors.initials: C
authors.lastname: Wang
authors.forename: Cara E
authors.initials: CE
authors.lastname: Moravec
authors.forename: Howard I
authors.initials: HI
authors.lastname: Sirotkin
authors.forename: Kai
authors.initials: K
authors.lastname: Ge
authors.forename: Gustavo
authors.initials: G
authors.lastname: Gutierrez-Cruz
authors.forename: Vittorio
authors.initials: V
authors.lastname: Sartorelli
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D047369:Chromatin Immunoprecipitation; D056466:Histone Demethylases / Q000378:metabolism*; D006657:Histones / Q000378:metabolism*; D008745:Methylation; D051379:Mice; D024510:Muscle Development; D012319:RNA Polymerase II / Q000378:metabolism*; D014157:Transcription Factors; D015027:Zebrafish
chemical_list: D006657:Histones; C502250:Supt6 protein, mouse; D014157:Transcription Factors; D056466:Histone Demethylases; C111778:Utx protein, mouse; D012319:RNA Polymerase II