title: Myogenesis is delayed in bovine fetal clones.
abstract: We have recently reported that maturation of the skeletal muscle is delayed in cloned calves during their first year postnatally. This delay could originate from perturbations in fetal myogenesis. The aim of this study was to evaluate the developmental characteristics of muscle in clones versus animals derived from conventional reproduction. We have characterized the anatomical and biochemical properties of the Semitendinosus muscle of clones versus controls at day 60 and day 260. We have analyzed the contractile and metabolic properties of muscle fibers by measuring the abundance of myosin heavy chain (MyHC) isoforms and activities of metabolic enzymes (LDH, PFK, COX, CS, ICDH), respectively. The spatial repartition of some components of the extracellular matrix (collagen types I, IV, VI, chondroitin-6-sulfate, decorin, and tenascin-X) was also studied. At day 60 we found lower numbers and structural organization of fibers, and a delay in the setup of the extracellular matrix. IGF-2 transcript abundance was lower in clones than in their controls. There was no difference in the expression of VEGF (a growth factor regulating vascularization and myogenesis) and its receptor. At day 260 the muscles of fetal clones have not reached the same degree of differentiation than controls as shown by their lower energy metabolisms and their MyHC pattern. These results show for the first time that disturbances in myogenesis occur early in fetal life in cloned cattle.
authors.affiliation: INRA, UR1213, Unité de Recherches sur les Herbivores, Equipe Croissance et Métabolisme du Muscle, Centre Clermont-Ferrand/Theix , 63122 Saint-Genès-Champanelle, France. cassar@clermont.inra.fr
authors.forename: Isabelle
authors.initials: I
authors.lastname: Cassar-Malek
authors.forename: Brigitte
authors.initials: B
authors.lastname: Picard
authors.forename: Catherine
authors.initials: C
authors.lastname: Jurie
authors.forename: Anne
authors.initials: A
authors.lastname: Listrat
authors.forename: Michel
authors.initials: M
authors.lastname: Guillomot
authors.forename: Pascale
authors.initials: P
authors.lastname: Chavatte-Palmer
authors.forename: Yvan
authors.initials: Y
authors.lastname: Heyman
mesh_terms: D000818:Animals; D001706:Biopsy; D002417:Cattle; D019976:Cloning, Organism / Q000379:methods*; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D024510:Muscle Development; D009132:Muscles / Q000378:metabolism; D018995:Myosin Heavy Chains / Q000737:chemistry; D011247:Pregnancy; D011270:Pregnancy, Animal; D020033:Protein Isoforms; D040262:Receptors, Vascular Endothelial Growth Factor / Q000378:metabolism; D012867:Skin / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis
chemical_list: D020033:Protein Isoforms; D042461:Vascular Endothelial Growth Factor A; D040262:Receptors, Vascular Endothelial Growth Factor; D018995:Myosin Heavy Chains