title: Spatial and temporal changes in myosin heavy chain gene expression in skeletal muscle development.
abstract: Seven myosin heavy chains (MyHC) are expressed in mammalian skeletal muscle in spatially and temporally regulated patterns. The timing, distribution, and quantitation of MyHC expression during development and early postnatal life of the mouse are reported here. The three adult fast MyHC RNAs (IIa, IIb, and IId/x) are expressed in the mouse embryo and each mRNA has a distinct temporal and spatial distribution. In situ hybridization analysis demonstrates expression of IIb mRNA by 14.5 dpc, which proceeds developmentally in a rostral to caudal pattern. IId/x and IIa mRNAs are detectable 2 days later. Ribonuclease protection assays demonstrate that the three adult fast genes are expressed at approximately equal levels relative to each other in the embryo but at quite low levels relative to the two developmental isoforms, embryonic and perinatal. Just after birth major changes in the relative proportions of different MyHC RNAs and protein occur. In all cases, RNA expression and protein expression appear coincident. The changes in MyHC RNA and protein expression are distinct in different muscles and are restricted in some cases to particular regions of the muscle and do not always reflect their distribution in the adult.
authors.affiliation: Department of Microbiology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York, 10461, USA.
authors.forename: B D
authors.initials: BD
authors.lastname: Lu
authors.forename: D L
authors.initials: DL
authors.lastname: Allen
authors.forename: L A
authors.initials: LA
authors.lastname: Leinwand
authors.forename: G E
authors.initials: GE
authors.lastname: Lyons
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D005314:Embryonic and Fetal Development; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D051379:Mice; D024510:Muscle Development; D018482:Muscle, Skeletal / Q000196:embryology* / Q000254:growth & development*; D018995:Myosin Heavy Chains / Q000235:genetics*; D020033:Protein Isoforms / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis
chemical_list: D020033:Protein Isoforms; D012333:RNA, Messenger; D018995:Myosin Heavy Chains