title: Developmental expression and cardiac transcriptional regulation of Myh7b, a third myosin heavy chain in the vertebrate heart.
abstract: The mammalian heart expresses two myosin heavy chain (MYH) genes (Myh6 and Myh7), which are major components of the thick filaments of the sarcomere. We have determined that a third MYH, MYH7B, is also expressed in the myocardium. Developmental analysis shows Myh7b expression in cardiac and skeletal muscle of Xenopus, chick and mouse embryos, and in smooth muscle tissues during later stages of mouse embryogenesis. Myh7b is also expressed in the adult human heart. The promoter region of the Myh7b gene shows remarkable similarity between diverse species, suggesting that transcriptional control mechanisms have been conserved. Using luciferase reporter analysis in rat cardiomyocytes, it can be shown that MEF2, GATA, and E-box regulatory elements are essential for efficient expression of the Myh7b gene. In addition two conserved elements that do not correspond to consensus binding sites for known transcription factors are also essential for full transcriptional activity of the Myh7b reporter. Finally, the Myh7b gene shows a transcriptional response similar to Myh6 in response to cardiac hypertrophy.
authors.affiliation: Department of Cellular and Molecular Medicine, University of Arizona Health Sciences Center, Tucson, Arizona 85724, USA.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Warkman
authors.forename: Samantha A
authors.initials: SA
authors.lastname: Whitman
authors.forename: Melanie K
authors.initials: MK
authors.lastname: Miller
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Garriock
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Schwach
authors.forename: Carol C
authors.initials: CC
authors.lastname: Gregorio
authors.forename: Paul A
authors.initials: PA
authors.lastname: Krieg
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D015153:Blotting, Western; D006332:Cardiomegaly / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D002642:Chick Embryo; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D006321:Heart / Q000196:embryology / Q000502:physiology*; D006801:Humans; D007124:Immunoenzyme Techniques; D017403:In Situ Hybridization; D008156:Luciferases / Q000378:metabolism; D051379:Mice / Q000196:embryology; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000166:cytology / Q000378:metabolism; D009206:Myocardium / Q000166:cytology / Q000378:metabolism; D018995:Myosin Heavy Chains / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014982:Xenopus laevis / Q000196:embryology
chemical_list: D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D008156:Luciferases; D018995:Myosin Heavy Chains