title: Developmental transitions in the myosin heavy chain phenotype of human respiratory muscle.
abstract: We studied the expression of myosin heavy chain (MHC) isoforms in the costal diaphragm (DIA) and the genioglossus (GG) muscles from 16 to 42 weeks gestation in the human using Western blotting techniques. Embryonic/neonatal MHC (MHCemb/neo) was the predominant isoform expressed in the DIA and GG at 16-24 weeks gestation. Subsequently, MHCemb/neo expression declined and the expression of MHCslow and MHC2A increased. At term, the DIA MHC phenotype was a composite of MHCemb/neo (15% of the total MHC complement), MHCslow (32%), MHC2A (47%), and MHC2B (6%); whereas, the GG was largely comprised of MHC2A (74%). We conclude that human DIA and GG demonstrate temporally dependent changes in MHC expression during gestation- and muscle-specific MHC phenotypes as they approach term.
authors.affiliation: Department of Pediatrics, University of Pittsburgh, School of Medicine, Pa., USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Lloyd
authors.forename: B S
authors.initials: BS
authors.lastname: Brozanski
authors.forename: M
authors.initials: M
authors.lastname: Daood
authors.forename: J F
authors.initials: JF
authors.lastname: Watchko
mesh_terms: D003964:Diaphragm / Q000196:embryology / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005333:Fetus / Q000378:metabolism; D005865:Gestational Age; D006801:Humans; D007366:Intercostal Muscles / Q000196:embryology / Q000378:metabolism; D018482:Muscle, Skeletal / Q000196:embryology* / Q000378:metabolism; D018995:Myosin Heavy Chains / Q000096:biosynthesis*; D010641:Phenotype; D012132:Respiratory Muscles / Q000196:embryology* / Q000378:metabolism
chemical_list: D018995:Myosin Heavy Chains