Ectopic expression of an embryonic skeletal myosin heavy chain in human fetal and Syrian hamster hearts.
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.
Minamisawa
Susumu
S
Department of Pediatric Cardiology, The Heart Institute of Japan, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan.
Hiratsuka
Eriko
E
Ruiz-Lozano
Pilar
P
Machida
Shuichi
S
Furutani
Yoshiyuki
Y
Nishimura
Masahiko
M
Takao
Atsuyoshi
A
Yanagisawa
Keiji
K
Momma
Kazuo
K
Saeki
Yasutake
Y
Matsuoka
Rumiko
R
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
D020033:Protein Isoforms; D018995:Myosin Heavy Chains