Tissue-specific expression and chromosome assignment of genes specifying two isoforms of subunit VIIa of human cytochrome c oxidase.
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.
Arnaudo
E
E
H. Houston Merritt Clinical Research Center for Muscular Dystrophy and Related Disorders, Columbia University College of Physicians and Surgeons, New York, NY 10032.
Hirano
M
M
Seelan
R S
RS
Milatovich
A
A
Hsieh
C L
CL
Fabrizi
G M
GM
Grossman
L I
LI
Francke
U
U
Schon
E A
EA
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002874:Chromosome Mapping; D002888:Chromosomes, Human, Pair 19; D030401:Cytochrome-c Oxidase Deficiency; D004247:DNA; D003576:Electron Transport Complex IV / Q000235:genetics*; D006801:Humans; D007527:Isoenzymes / Q000235:genetics*; D008969:Molecular Sequence Data; D009132:Muscles / Q000201:enzymology*; D009928:Organ Specificity / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic
D007527:Isoenzymes; D004247:DNA; D003576:Electron Transport Complex IV