title: Direct molecular regulation of the myogenic determination gene Myf5 by Pax3, with modulation by Six1/4 factors, is exemplified by the -111 kb-Myf5 enhancer.
abstract: The Myf5 gene plays an important role in myogenic determination during mouse embryo development. Multiple genomic regions of the Mrf4-Myf5 locus have been characterised as enhancer sequences responsible for the complex spatiotemporal expression of the Myf5 gene at the onset of myogenesis. These include an enhancer sequence, located at -111 kb upstream of the Myf5 transcription start site, which is responsible of Myf5 activation in ventral somitic domains (Ribas et al., 2011. Dev. Biol. 355, 372-380). We show that the -111 kb-Myf5 enhancer also directs transgene expression in some limb muscles, and is active at foetal as well as embryonic stages. We have carried out further characterisation of the regulation of this enhancer and show that the paired-box Pax3 transcription factor binds to it in vitro as in vivo, and that Pax binding sites are essential for its activity. This requirement is independent of the previously reported regulation by TEAD transcription factors. Six1/4 which, like Pax3, are important upstream regulators of myogenesis, also bind in vivo to sites in the -111 kb-Myf5 enhancer and modulate its activity. The -111 kb-Myf5 enhancer therefore shares common functional characteristics with another Myf5 regulatory sequence, the hypaxial and limb 145 bp-Myf5 enhancer, both being directly regulated in vivo by Pax3 and Six1/4 proteins. However, in the case of the -111 kb-Myf5 enhancer, Six has less effect and we conclude that Pax regulation plays a major role in controlling this aspect of the Myf5 gene expression at the onset of myogenesis in the embryo.
authors: Centre National de la Recherche Scientifique URA 2578, Department of Developmental and Stem Cell Biology, Pasteur Institute, 25 rue du Dr Roux, 75015 Paris, France.
authors: Philippe
authors: P
authors: Daubas
authors: Margaret E
authors: ME
authors: Buckingham
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D051837:COUP Transcription Factor II / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence / Q000379:methods; D008954:Models, Biological; D008957:Models, Genetic; D008969:Molecular Sequence Data; D024510:Muscle Development; D051787:Myogenic Regulatory Factor 5 / Q000235:genetics* / Q000502:physiology*; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors / Q000235:genetics* / Q000502:physiology*; D010957:Plasmids / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D015534:Trans-Activators / Q000378:metabolism*
chemical_list: D051837:COUP Transcription Factor II; D018398:Homeodomain Proteins; C497418:Myf5 protein, mouse; D051787:Myogenic Regulatory Factor 5; C497587:Nr2f2 protein, mouse; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors; C490947:Six1 protein, mouse; C098490:Six4 protein, mouse; D015534:Trans-Activators; C068686:Pax3 protein, mouse