title: Steady-state transcript levels of cytochrome c oxidase genes during human myogenesis indicate subunit switching of subunit VIa and co-expression of subunit VIIa isoforms.
abstract: Steady-state levels of the mitochondrial rRNAs, of mRNAs for mitochondrially and nuclear-encoded subunits of cytochrome c oxidase and for the beta subunit of ATP synthase were assessed by Northern blot hybridizations during the in vitro differentiation of human myoblasts. Transcript levels of the so-called liver-type form of subunit VIa of cytochrome c oxidase diminished during the course of differentiation, while transcription of the so-called heart-type form was induced. Transcripts for the liver-type form and for the heart-type form of subunit VIIa of cytochrome c oxidase were detected in all myogenic cultures; the levels of the heart-type form progressively increased during the course of differentiation. The levels of the other transcripts studied did not change substantially. The results suggest subunit switching of subunit VIa and co-expression of subunit VIIa isoforms during myogenesis. The differential changes in mRNA levels of the heart-type subunits VIa and VIIa and the differential changes in mRNA levels of the liver-type subunits VIa and VIIa demonstrate that different transcriptional regulation mechanisms are present for both heart-type genes as well as for both liver-type genes.
authors.affiliation: Laboratory of Physiological Chemistry, University of Groningen, Netherlands.
authors.forename: J W
authors.initials: JW
authors.lastname: Taanman
authors.forename: N H
authors.initials: NH
authors.lastname: Herzberg
authors.forename: H
authors.initials: H
authors.lastname: De Vries
authors.forename: P A
authors.initials: PA
authors.lastname: Bolhuis
authors.forename: C
authors.initials: C
authors.lastname: Van den Bogert
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000328:Adult; D002478:Cells, Cultured; D003576:Electron Transport Complex IV / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008931:Mitochondria, Muscle / Q000201:enzymology / Q000378:metabolism; D009132:Muscles / Q000166:cytology / Q000201:enzymology*; D012333:RNA, Messenger / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D007527:Isoenzymes; D012333:RNA, Messenger; D012336:RNA, Ribosomal, 16S; D003576:Electron Transport Complex IV; D000251:Adenosine Triphosphatases