Isolation of cDNAs encoding subunit VIb of cytochrome c oxidase and steady-state levels of coxVIb mRNA in different tissues.
A full-length cDNA clone specifying the nuclear-encoded subunit VIb of human cytochrome c oxidase (COX) was isolated from a human skeletal muscle cDNA expression library. This was done with antiserum directed against the group of subunits VIa, b and c of bovine heart COX. A potential ribosome-binding site was located immediately upstream from the initiation codon. The predicted amino acid sequence revealed 85% similarity with the corresponding subunit of bovine heart COX. Subunit VIb lacks a cleavable presequence for mitochondrial addressing. We assume that there are no tissue-specific isoforms of subunit VIb, since (i) in a Northern blot experiment a single hybridizing band of approx. 500 nucleotides was demonstrated in RNA from liver, skeletal muscle, MOLT-4 cells and fibroblasts and (ii) a full-length cDNA clone with an identical sequence was isolated from a human liver cDNA library. Steady-state levels of the coxVIb transcript were different in the tissues examined.
Taanman
J W
JW
Laboratory of Physiological Chemistry, University of Groningen, The Netherlands.
Schrage
C
C
Ponne
N J
NJ
Das
A T
AT
Bolhuis
P A
PA
de Vries
H
H
Agsteribbe
E
E
D001483:Base Sequence; D003576:Electron Transport Complex IV / Q000235:genetics*; D015723:Gene Library; D006801:Humans; D008099:Liver / Q000201:enzymology; D008969:Molecular Sequence Data; D009132:Muscles / Q000201:enzymology; D012333:RNA, Messenger / Q000032:analysis
D012333:RNA, Messenger; D003576:Electron Transport Complex IV