title: Muscle development and differentiation in the urodele  Ambystoma mexicanum.
abstract: Muscle differentiation has been widely described in zebrafish and Xenopus, but nothing is known about this process in amphibian urodeles. Both anatomical features and locomotor activity in urodeles are known to show intermediate features between fish and anurans. Therefore, a better understanding of myogenesis in urodeles could be useful to clarify the evolutionary changes that led to the formation of skeletal muscle in the trunk of land vertebrates. We report here a detailed morphological and molecular investigation on several embryonic stages of Ambystoma mexicanum and show that the first differentiating muscle fibers are the slow ones, originating from a myoblast population initially localized close to the notochord that forms a superficial layer on the somitic surface afterwards. Subsequently, fast fibers differentiation ensues. We also identified and cloned A. mexicanum Myf5 as a muscle-specific transcriptional factor likely involved in urodele muscle differentiation.
authors.affiliation: Department of Biotechnology and Life Science, University of Insubria, via J.H. Dunant 3, 21100, Varese, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Banfi
authors.forename: Laura
authors.initials: L
authors.lastname: Monti
authors.forename: Francesco
authors.initials: F
authors.lastname: Acquati
authors.forename: Gianluca
authors.initials: G
authors.lastname: Tettamanti
authors.forename: Magda
authors.initials: M
authors.lastname: de Eguileor
authors.forename: Annalisa
authors.initials: A
authors.lastname: Grimaldi
mesh_terms: D000558:Ambystoma mexicanum / Q000033:anatomy & histology / Q000196:embryology* / Q000235:genetics; D000818:Animals; D019521:Body Patterning; D002454:Cell Differentiation; D003001:Cloning, Molecular; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000648:ultrastructure; D047108:Embryonic Development; D057075:Enzyme Assays; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D024510:Muscle Development; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism / Q000648:ultrastructure; D018657:Muscle Fibers, Slow-Twitch / Q000378:metabolism / Q000648:ultrastructure; D018482:Muscle, Skeletal / Q000196:embryology / Q000648:ultrastructure; D032448:Myoblasts, Skeletal / Q000378:metabolism; D051787:Myogenic Regulatory Factor 5 / Q000235:genetics / Q000378:metabolism; D009218:Myosins / Q000235:genetics / Q000378:metabolism; D009672:Notochord / Q000196:embryology / Q000648:ultrastructure; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D051787:Myogenic Regulatory Factor 5; D020033:Protein Isoforms; D012333:RNA, Messenger; D009218:Myosins