Myosin isoenzymes and their subunits in urodelan amphibian fast skeletal muscle. Coexistence of larval and adult heavy chains in neotenic individuals.
The distributions of native myosin isoforms were examined by electrophoresis under non-dissociating conditions, in the fast twitch dorsal skeletal muscle of young larvae, neotenic adults and metamorphosed adults of urodelan amphibians. Both heavy and light chains of myosin isoenzymes were analysed. In pyrophosphate acrylamide gel electrophoresis three isoenzymes were demonstrated in larval myosin; other isoforms of lower electrophoretic mobility were observed in metamorphosed adults myosin. Larval and adult isoenzymes were shown to coexist in myosin from neotenic adults. Analysis of heavy chains in denaturing conditions and proteolytic digestion revealed the sequential occurrence during development of two types of heavy chains, one larval and one adult, that coexist in the myosin of neotenic adults only. Analysis of light chain patterns under denaturing conditions revealed the existence of three fast light chains which displayed no modification during the course of development. The neotenic urodelan amphibian species model represents actually the only model in which the coexistence of larval (or neonatal) and adult heavy chains is maintained throughout life in adults.
Chanoine
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Laboratoire de Biologie du Développement, Université René Descartes, Paris, France.
Gallien
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D000375:Aging; D000557:Ambystoma / Q000254:growth & development*; D000558:Ambystoma mexicanum / Q000254:growth & development*; D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism*; D007814:Larva; D046911:Macromolecular Substances; D008675:Metamorphosis, Biological; D008970:Molecular Weight; D009132:Muscles / Q000201:enzymology*; D009218:Myosins / Q000302:isolation & purification / Q000378:metabolism*; D010446:Peptide Fragments / Q000302:isolation & purification; D010999:Pleurodeles / Q000254:growth & development*; D012455:Salamandridae / Q000254:growth & development*
D007527:Isoenzymes; D046911:Macromolecular Substances; D010446:Peptide Fragments; D009218:Myosins