title: Mrf4 (myf6) is dynamically expressed in differentiated zebrafish skeletal muscle.
abstract: Mrf4 (Myf6) is a member of the basic helix-loop-helix (bHLH) myogenic regulatory transcription factor (MRF) family, which also contains Myod, Myf5 and myogenin. Mrf4 is implicated in commitment of amniote cells to skeletal myogenesis and is also abundantly expressed in many adult muscle fibres. The specific role of Mrf4 is unclear both because mrf4 null mice are viable, suggesting redundancy with other MRFs, and because of genetic interactions at the complex mrf4/myf5 locus. We report the cloning and expression of an mrf4 gene from zebrafish, Danio rerio, which shows conservation of linkage to myf5. Mrf4 mRNA accumulates in a subset of terminally differentiated muscle fibres in parallel with myosin protein in the trunk and fin. Although most, possibly all, trunk muscle expresses mrf4, the level of mRNA is dynamically regulated. No expression is detected in muscle precursor cell populations prior to myosin accumulation. Moreover, mrf4 expression is not detected in head muscles, at least at early stages. As fish mature, mrf4 expression is pronounced in the region of slow muscle fibres.
authors.affiliation: MRC Centre for Developmental Neurobiology and Randall Division of Cell and Molecular Biophysics, 4th Floor South, New Hunt's House, Guy's Campus, King's College London, London SE1 1UL, UK.
authors.forename: Yaniv
authors.initials: Y
authors.lastname: Hinits
authors.forename: Daniel P S
authors.initials: DP
authors.lastname: Osborn
authors.forename: Jaime J
authors.initials: JJ
authors.lastname: Carvajal
authors.forename: Peter W J
authors.initials: PW
authors.lastname: Rigby
authors.forename: Simon M
authors.initials: SM
authors.lastname: Hughes
mesh_terms: D000595:Amino Acid Sequence; D000650:Amnion / Q000166:cytology; D000818:Animals; D024722:Cardiac Myosins / Q000096:biosynthesis / Q000502:physiology; D005786:Gene Expression Regulation; D008954:Models, Biological; D008969:Molecular Sequence Data; D009132:Muscles / Q000378:metabolism; D051787:Myogenic Regulatory Factor 5 / Q000378:metabolism; D018006:Myogenic Regulatory Factors / Q000096:biosynthesis* / Q000502:physiology*; D018008:Myogenin / Q000378:metabolism; D018994:Myosin Light Chains / Q000096:biosynthesis / Q000502:physiology; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D015027:Zebrafish
chemical_list: D051787:Myogenic Regulatory Factor 5; D018006:Myogenic Regulatory Factors; D018008:Myogenin; D018994:Myosin Light Chains; C063403:myogenic factor 6; C107184:myosin light chain 2; D024722:Cardiac Myosins