title: Ectopic expression of an embryonic skeletal myosin heavy chain in human fetal and Syrian hamster hearts.
abstract: The mammalian heart is known to contain only two isoformic myosin heavy chain (MHC) genes, alpha and beta. A previously uncharacterized MHC gene was isolated in Syrian hamster hearts (McCully et al., JMol Biol 1991). We identified the novel MHC gene as a hamster embryonic skeletal MHC gene based on the developmental stage- and tissue-specific expression pattern: the restricted expression ofmRNA to striated muscles was highest in embryonic skeletal muscle and was developmentally down-regulated. We confirmed that the embryonic skeletal MHC gene exhibited higher expression in cardiomyopathic than in normal hamster hearts, and was up-regulated during the development of cardiomyopathy. The sporadic expression was highly localized in the endocardium. The present study identified that a very small number of undifferentiated myogenic cells existed in adult hamster endocardium. Moreover, using RT-PCR, a homologue of embryonic skeletal MHC mRNA was also expressed in human embryonic, but not adult ventricles. Our data provide a new insight into the regulatory mechanisms of MHCs in the cardiomyopathic hamster heart.
authors.affiliation: Department of Pediatric Cardiology, The Heart Institute of Japan, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Minamisawa
authors.forename: Eriko
authors.initials: E
authors.lastname: Hiratsuka
authors.forename: Pilar
authors.initials: P
authors.lastname: Ruiz-Lozano
authors.forename: Shuichi
authors.initials: S
authors.lastname: Machida
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Furutani
authors.forename: Masahiko
authors.initials: M
authors.lastname: Nishimura
authors.forename: Atsuyoshi
authors.initials: A
authors.lastname: Takao
authors.forename: Keiji
authors.initials: K
authors.lastname: Yanagisawa
authors.forename: Kazuo
authors.initials: K
authors.lastname: Momma
authors.forename: Yasutake
authors.initials: Y
authors.lastname: Saeki
authors.forename: Rumiko
authors.initials: R
authors.lastname: Matsuoka
mesh_terms: D000818:Animals; D009202:Cardiomyopathies / Q000235:genetics / Q000378:metabolism; D006224:Cricetinae; D004622:Embryo, Mammalian / Q000378:metabolism; D005318:Fetal Heart / Q000378:metabolism*; D006801:Humans; D008647:Mesocricetus; D009206:Myocardium / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000235:genetics* / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism
chemical_list: D020033:Protein Isoforms; D018995:Myosin Heavy Chains