title: Positive and negative regulation of muscle cell identity by members of the hedgehog and TGF-beta gene families.
abstract: We have examined whether the development of embryonic muscle fiber type is regulated by competing influences between Hedgehog and TGF-beta signals, as previously shown for development of neuronal cell identity in the neural tube. We found that ectopic expression of Hedgehogs or inhibition of protein kinase A in zebrafish embryos induces slow muscle precursors throughout the somite but muscle pioneer cells only in the middle of the somite. Ectopic expression in the notochord of Dorsalin-1, a member of the TGF-beta superfamily, inhibits the formation of muscle pioneer cells, demonstrating that TGF-beta signals can antagonize the induction of muscle pioneer cells by Hedgehog. We propose that a Hedgehog signal first induces the formation of slow muscle precursor cells, and subsequent Hedgehog and TGF-beta signals exert competing positive and negative influences on the development of muscle pioneer cells.
authors.affiliation: Howard Hughes Medical Institute, University of Washington, School of Medicine, Seattle 98195, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Du
authors.forename: S H
authors.initials: SH
authors.lastname: Devoto
authors.forename: M
authors.initials: M
authors.lastname: Westerfield
authors.forename: R T
authors.initials: RT
authors.lastname: Moon
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology; D015536:Down-Regulation / Q000235:genetics*; D004330:Drosophila; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian; D018507:Gene Expression Regulation, Developmental; D053823:Hedgehog Proteins; D019476:Insect Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D005810:Multigene Family; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000201:enzymology / Q000502:physiology*; D018657:Muscle Fibers, Slow-Twitch / Q000166:cytology / Q000502:physiology; D009672:Notochord / Q000378:metabolism; D015398:Signal Transduction; D016212:Transforming Growth Factor beta / Q000235:genetics* / Q000502:physiology; D015291:Transforming Growth Factors / Q000096:biosynthesis / Q000502:physiology; D015854:Up-Regulation / Q000235:genetics*; D015027:Zebrafish; D029961:Zebrafish Proteins
chemical_list: D029721:Drosophila Proteins; D053823:Hedgehog Proteins; D019476:Insect Proteins; D016212:Transforming Growth Factor beta; D029961:Zebrafish Proteins; C077245:hh protein, Drosophila; D015291:Transforming Growth Factors; D017868:Cyclic AMP-Dependent Protein Kinases