title: CMF1-Rb interaction promotes myogenesis in avian skeletal myoblasts.
abstract: CMF1 protein is expressed in developing striated muscle before the expression of contractile proteins, and depletion of CMF1 in myoblasts results in inability to express muscle-specific proteins. Previous studies of CMF1 identify a functional Rb-binding domain, which is conserved in the murine and human homologues. Here, we show that CMF1 binds Rb family members, while a CMF1 protein with deletion of the Rb-binding domain (Rb-del CMF1) does not. Myogenic cell lines over-expressing Rb-del CMF1 proliferate normally, but exhibit markedly impaired differentiation, including dramatically reduced contractile proteins gene expression and failure to fuse into myotubes. Furthermore, by quantitative real-time polymerase chain reaction, MyoD and Myf5 mRNA levels are comparable to wild-type, while myogenin and contractile protein mRNA levels are significantly attenuated. These data demonstrate that CMF1 regulates myocyte differentiation by interaction with Rb family members to induce expression of myogenic regulatory factors.
authors.affiliation: Department Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
authors.forename: J Brian
authors.initials: JB
authors.lastname: Robertson
authors.forename: Tianli
authors.initials: T
authors.lastname: Zhu
authors.forename: Shampa
authors.initials: S
authors.lastname: Nasreen
authors.forename: Dawn
authors.initials: D
authors.lastname: Kilkenny
authors.forename: David
authors.initials: D
authors.lastname: Bader
authors.forename: Ellen
authors.initials: E
authors.lastname: Dees
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D049109:Cell Proliferation; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D003285:Contractile Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D008840:Microfilament Proteins; D024510:Muscle Development / Q000502:physiology*; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000166:cytology / Q000502:physiology*; D017570:MyoD Protein / Q000235:genetics / Q000378:metabolism; D032446:Myoblasts / Q000166:cytology / Q000502:physiology*; D032383:Myocytes, Cardiac / Q000502:physiology; D051787:Myogenic Regulatory Factor 5 / Q000235:genetics / Q000378:metabolism; D018008:Myogenin / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D011784:Quail; D016160:Retinoblastoma Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D003285:Contractile Proteins; D008840:Microfilament Proteins; D009124:Muscle Proteins; C497418:Myf5 protein, mouse; D017570:MyoD Protein; D051787:Myogenic Regulatory Factor 5; D018008:Myogenin; D016160:Retinoblastoma Protein; C094772:centromere protein F