Differential expression of genes specifying two isoforms of subunit VIa of human cytochrome c oxidase

Gene. 1992 Oct 1;119(2):307-12. doi: 10.1016/0378-1119(92)90288-z.


Subunit VIa of mammalian cytochrome c oxidase (COX; EC exists in two isoforms, one present ubiquitously ('liver' isoform; COX VIa-L) and the other present only in cardiac and skeletal muscle (COX VIa-M). We have now isolated a full-length cDNA specifying human COX VIa-M. The deduced mature COX VIa-M polypeptide is 62% identical to the human COX VIa-L isoform, but is approximately 80% identical to the bovine and rat COX VIa-M isoforms, suggesting that the two COX VIa isoform-encoding genes arose prior to the mammalian radiation. Transcriptional analysis showed a tissue-specific pattern: whereas COXVIa-L is transcribed ubiquitously, COXVIa-M is transcribed only in heart and skeletal muscle. The cDNA specifying COX VIa-M is a prime candidate for use in investigations of Mendelian-inherited COX deficiencies with primary involvement of muscle.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Blotting, Northern
  • Cytochrome-c Oxidase Deficiency
  • DNA
  • Electron Transport Complex IV / genetics*
  • Gene Expression Regulation, Enzymologic
  • Humans
  • Isoenzymes / genetics*
  • Molecular Sequence Data
  • Muscles / enzymology*
  • Organ Specificity / genetics
  • Sequence Homology, Amino Acid
  • Sequence Homology, Nucleic Acid
  • Transcription, Genetic


  • Isoenzymes
  • DNA
  • Electron Transport Complex IV

Associated data

  • GENBANK/D10364
  • GENBANK/D10365
  • GENBANK/D10366
  • GENBANK/M74891
  • GENBANK/M74892
  • GENBANK/M79309
  • GENBANK/M79310
  • GENBANK/M83308
  • GENBANK/M90357
  • GENBANK/S43297