Windner, S. E.Doris, R. A.Ferguson, C. M.Nelson, A. C.Valentin, G.Tan, H.Oates, A. C.Wardle, F. C.Devoto, S. H.2017-05-302017-05-302017-05-30201510.1242/dev.1134312-s2.0-84930531867https://infoscience.epfl.ch/handle/20.500.14299/137745During embryonic development, the paraxial mesoderm becomes segmented into somites, within which proliferative muscle progenitors and muscle fibers establish the skeletal musculature. Here, we demonstrate that a gene network previously implicated in somite boundary formation, involving the transcriptional regulators Tbx6, Mesp-b and Ripply1, also confers spatial and temporal regulation to skeletal myogenesis in zebrafish. We show that Tbx6 directly regulates mesp-b and ripply1 expression in vivo, and that the interactions within the regulatory network are largely conserved among vertebrates. Mesp-b is necessary and sufficient for the specification of a subpopulation of muscle progenitors, the central proportion of the Pax3+/Pax7+ dermomyotome. Conditional ubiquitous expression indicates that Mesp-b acts by inhibiting myogenic differentiation and by inducing the dermomyotome marker meox1. By contrast, Ripply1 induces a negative-feedback loop by promoting Tbx6 protein degradation. Persistent Tbx6 expression in Ripply1 knockdown embryos correlates with a deficit in dermomyotome and myotome marker gene expression, suggesting that Ripply1 promotes myogenesis by terminating Tbx6-dependent inhibition of myogenic maturation. Together, our data suggest that Mesp-b is an intrinsic upstream regulator of skeletal muscle progenitors and that, in zebrafish, the genes regulating somite boundary formation also regulate the development of the dermomyotome in the anterior somite compartment. © 2015. Published by The Company of Biologists Ltd.animalanimal cellAnimalsanterior posterior axisAntibodiesantibody labelingArticleBase Sequencebasic helix loop helix transcription factorBasic Helix-Loop-Helix Transcription Factorscell differentiationcell maturationchromatin immunoprecipitationcontrolled studyDanio rerioDevelopmentalDNADNA sequenceembryoEmbryologyfast muscle fibergene controlGene expressiongene expression regulationGene Knockdown Techniquesgene regulatory networkGene Regulatory Networksgene silencingGenetically ModifiedGeneticsheat shockhigh throughput sequencingimmunohistochemistryImmunologyin situ hybridizationin vivo studymarker genemeox1 proteinmesodermmespb proteinmetabolismmolecular geneticsMolecular Sequence DataMonoclonalmonoclonal antibodymorpholino oligonucleotideMorpholinosMusclemuscle developmentmyotomenegative feedbacknonhumannotochordnuclear proteinNuclear Proteinsnucleotide sequencephenotypePhysiologypriority journalprotein degradationprotein expressionprotein functionReverse Transcriptase Polymerase Chain Reactionreverse transcription polymerase chain reactionripply1 proteinSequence AnalysisSkeletalskeletal muscleslow muscle fibersomiteSomitesT-Box Domain ProteinsT box transcription factortbx6 proteintranscription factortranscription factor Mesp btranscription factor PAX3transcription factor PAX7transcription factor Ripply1transcription factor TBX6transcription initiation sitetranscription regulationtransgenic animalunclassified drugupregulationVertebratazebra fishzebrafishzebrafish proteinZebrafish Proteinstext::journal::journal article::research article