title: Analysis of myosin isoform transitions during growth and development in diverse chicken genotypes.
abstract: The temporal expression of chicken skeletal fast myosin heavy chain (MyHC) isoforms in pectoralis major muscle was characterized in 3 commercial broiler lines at embryonic d 19 and at 7, 14, and 21 d posthatch. Lines A and B have been selected for breast yield, and line C is a fast' growing commercial line with limited selection for carcass traits. The isoform transitions in breast muscle samples were compared with samples from Single Comb White Leghorns (line D) using a semiquantitative immunoassay. The hypothesis was that selection for growth and carcass development in broilers would be accompanied by changes in the temporal expression of one or more of the chicken fast MyHC isoforms. Embryos from all lines were sampled at 19 d of incubation, and chicks were randomly sampled at 7, 14, and 21 d post-hatch. Myosin was extracted from pectoralis major muscle and assayed for purity and total protein concentration by SDS-PAGE and bincinchoninic acid protein analyses, respectively. The relative concentration of MyHC isoforms was evaluated by semiquantitative ELISA with 3 monoclonal antibodies specific for chicken skeletal fast embryonic and adult (eMyHC, aMyHC; EB165), neonatal (nMyHC; 2E9), and adult (aMyHC; AB8) myosin, respectively. The overall temporal expression of the myosin isoforms, eMyHC, nMyHC, and aMyHC, was similar in all lines. With eMyHC, at 19 d of incubation, line B had lower expression than lines A, C, and D. Expression of nMyHC, in lines C and D was similar with expression being highest at 7 d and lower at 14 d and 21 d. In lines A and B, however, nMyHC expression was higher at hatch than lines C and D. In line D, aMyHC was expressed at 14 d and increased through 21 d, whereas in lines A, B, and C, aMyHC isoform was expressed and was higher at 7 d and increased through 21 d. The results of this experiment support our hypothesis that commercial broilers have different temporal expression patterns of the developmental chicken fast MyHC isoforms.
authors.affiliation: Department of Animal Sciences, 2029 Fyffe Road, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Reddish
authors.forename: M
authors.initials: M
authors.lastname: Wick
authors.forename: N R
authors.initials: NR
authors.lastname: St-Pierre
authors.forename: M S
authors.initials: MS
authors.lastname: Lilburn
mesh_terms: D000375:Aging / Q000235:genetics; D000818:Animals; D001835:Body Weight; D002645:Chickens / Q000235:genetics* / Q000254:growth & development*; D018507:Gene Expression Regulation, Developmental; D005838:Genotype; D018482:Muscle, Skeletal / Q000378:metabolism; D009218:Myosins / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism
chemical_list: D020033:Protein Isoforms; D009218:Myosins