title: Pax3 and Pax7 expression and regulation in the avian embryo.
abstract: Satellite cells are essential for postnatal growth and repair of skeletal muscle. The paired-box transcription factors Pax3 and Pax7 are expressed in emerging muscle precursors. Recent studies have traced the origin of satellite cells to the embryonic dermomyotome, however, their developmental regulation throughout embryogenesis remains unclear. We show the overlying surface ectoderm and lateral plate are essential for Pax3 expression, and that the overlying surface ectoderm and neural tube are necessary for Pax7 expression within the dorsal somite. Furthermore we show that the notochord acts to down regulate the expression of both genes. Moreover, we identify diffusible factors within these tissues that act to maintain expression of Pax3 ( + ) and Pax7 (+) muscle precursors. We show that Wnt1, 3a, 4 and 6 proteins are able to up regulate and expand the expression of Pax3 and Pax7 within the dorsal somite. Finally, we show that Wnt6 can mimic the effect of the dorsal ectoderm to maintain Pax3 and Pax7 expression.
authors.affiliation: Department Veterinary Basic Sciences, Royal Veterinary College, Royal College Street, NW1 OUT, London, UK.
authors.forename: Anthony
authors.initials: A
authors.lastname: Otto
authors.forename: Corina
authors.initials: C
authors.lastname: Schmidt
authors.forename: Ketan
authors.initials: K
authors.lastname: Patel
mesh_terms: D000818:Animals; D002460:Cell Line; D002465:Cell Movement; D017690:Cell Transplantation; D002642:Chick Embryo; D004475:Ectoderm / Q000166:cytology / Q000378:metabolism*; D004627:Embryonic Induction; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D018878:Limb Buds / Q000166:cytology / Q000378:metabolism; D008648:Mesoderm / Q000166:cytology / Q000378:metabolism*; D024510:Muscle Development; D018482:Muscle, Skeletal / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D009432:Neural Crest / Q000166:cytology / Q000378:metabolism*; D051763:PAX7 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D014162:Transfection; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism; D051155:Wnt1 Protein / Q000235:genetics / Q000378:metabolism; D060508:Wnt3 Protein; D060528:Wnt4 Protein
chemical_list: D051763:PAX7 Transcription Factor; D012333:RNA, Messenger; D051153:Wnt Proteins; D051155:Wnt1 Protein; D060508:Wnt3 Protein; D060528:Wnt4 Protein