Arnaudo E, Hirano M, Seelan R S, Milatovich A, Hsieh C L, Fabrizi G M, Grossman L I, Francke U, Schon E A
H. Houston Merritt Clinical Research Center for Muscular Dystrophy and Related Disorders, Columbia University College of Physicians and Surgeons, New York, NY 10032.
Gene. 1992 Oct 1;119(2):299-305. doi: 10.1016/0378-1119(92)90287-y.
Subunit VIIa of mammalian cytochrome c oxidase (COX; EC 1.9.3.1) exists in at least two isoforms, one present in all tissue types ('liver' isoform; COX VIIa-L) and the other specific for cardiac and skeletal muscle (COX VIIa-M). We have isolated a full-length cDNA encoding human COX VIIa-M. The deduced polypeptide represents the human ortholog of COX VIIa-M, as it shares 78% identity with bovine COX VIIa-M, but only 63% identity with human COX VIIa-L. Northern-blot analysis of primate tissues demonstrated that COXVIIa-M mRNA is present only in muscle tissues; in contrast, the COXVIIa-L mRNA is present in both muscle and nonmuscle tissues. Southern-blot hybridization of human-rodent cell hybrid genomic DNA indicates that the COXVIIa-M gene maps to a single locus on chromosome 19, designated COX7AM. In contrast, COXVIIa-L cDNA probes hybridized to fragments from two COX7AL loci, on chromosomes 4 and 14.
