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

Gian Maria Fabrizi, James Sadlock, Michio Hirano, Shuji Mita, Yasutoshi Koga, Rosario Rizzuto, Massimo Zeviani, Eric A. Schon

Research output: Contribution to journalArticlepeer-review


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 Vla-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 deficiences with primary involvement of muscle.

Original languageEnglish
Pages (from-to)307-312
Number of pages6
Issue number2
Publication statusPublished - Oct 1 1992


  • electron transport
  • liver
  • Mitochondrial protein
  • muscle
  • nuclear gene
  • nucleotide sequence analysis
  • recombinant DNA
  • respiratory chain

ASJC Scopus subject areas

  • Genetics


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