title: Baf60c is essential for function of BAF chromatin remodelling complexes in heart development.
abstract: Tissue-specific transcription factors regulate several important aspects of embryonic development. They must function in the context of DNA assembled into the higher-order structure of chromatin. Enzymatic complexes such as the Swi/Snf-like BAF complexes remodel chromatin to allow the transcriptional machinery access to gene regulatory elements. Here we show that Smarcd3, encoding Baf60c, a subunit of the BAF complexes, is expressed specifically in the heart and somites in the early mouse embryo. Smarcd3 silencing by RNA interference in mouse embryos derived from embryonic stem cells causes defects in heart morphogenesis that reflect impaired expansion of the anterior/secondary heart field, and also results in abnormal cardiac and skeletal muscle differentiation. An intermediate reduction in Smarcd3 expression leads to defects in outflow tract remodelling reminiscent of human congenital heart defects. Baf60c overexpressed in cell culture can mediate interactions between cardiac transcription factors and the BAF complex ATPase Brg1, thereby potentiating the activation of target genes. These results reveal tissue-specific and dose-dependent roles for Baf60c in recruiting BAF chromatin remodelling complexes to heart-specific enhancers, providing a novel mechanism to ensure transcriptional regulation during organogenesis.
authors.affiliation: Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada.
authors.forename: Heiko
authors.initials: H
authors.lastname: Lickert
authors.forename: Jun K
authors.initials: JK
authors.lastname: Takeuchi
authors.forename: Ingo
authors.initials: I
authors.lastname: Von Both
authors.forename: Johnathon R
authors.initials: JR
authors.lastname: Walls
authors.forename: Fionnuala
authors.initials: F
authors.lastname: McAuliffe
authors.forename: S Lee
authors.initials: SL
authors.lastname: Adamson
authors.forename: R Mark
authors.initials: RM
authors.lastname: Henkelman
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Wrana
authors.forename: Janet
authors.initials: J
authors.lastname: Rossant
authors.forename: Benoit G
authors.initials: BG
authors.lastname: Bruneau
mesh_terms: D000818:Animals; D042002:Chromatin Assembly and Disassembly / Q000502:physiology*; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D050991:GATA4 Transcription Factor; D018507:Gene Expression Regulation, Developmental; D006321:Heart / Q000196:embryology*; D006330:Heart Defects, Congenital / Q000235:genetics / Q000378:metabolism; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D047468:Immunoprecipitation; D017403:In Situ Hybridization; D051379:Mice; D008822:Mice, Transgenic; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D019170:Somites / Q000378:metabolism; D020825:T-Box Domain Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D050991:GATA4 Transcription Factor; C484171:Gata4 protein, mouse; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; D046912:Multiprotein Complexes; D009124:Muscle Proteins; C484469:Nkx2-5 protein, mouse; D021122:Protein Subunits; D012333:RNA, Messenger; C494056:Smarcd2 protein, mouse; C494055:Smarcd3 protein, mouse; D020825:T-Box Domain Proteins; C103172:T-box transcription factor 5; D014157:Transcription Factors