Yeast ubiquinol: cytochrome c oxidoreductase is still active after inactivation of the gene encoding the 17-kDa subunit VI.
The single nuclear gene encoding the 17-kDa subunit VI of yeast ubiquinol: cytochrome c oxidoreductase has been inactivated by one-step gene disruption. Disruption was verified by Southern blot analysis of nuclear DNA and immunoblotting. Cells lacking the 17-kDa protein are still capable of growth on glycerol and they contain all other subunits of complex III at wild-type levels, implying that the 17-kDa subunit is not essential for either assembly of complex III, or its function. In vitro, electron transport activity of complex III of mutant cells is about 40% of the wild-type complex, but for the total respiratory chain no significant differences in activity was measured between mutant and wild type. The energy-transducing capacity of the complex is not reduced in the absence of the 17-kDa protein. In a relatively high proportion of the transformants, disruption of the 17-kDa gene was accompanied by the appearance of a second mutation causing a petite phenotype. In these cells which lack cytochrome b, the presence of the 17-kDa protein (after complementation) results in stabilization of cytochrome c1.
Schoppink
P J
PJ
Laboratory of Biochemistry, University of Amsterdam, The Netherlands.
Hemrika
W
W
Reynen
J M
JM
Grivell
L A
LA
Berden
J A
JA
D004579:Electron Transport; D014450:Electron Transport Complex III / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D005786:Gene Expression Regulation; D005800:Genes, Fungal; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism; D008970:Molecular Weight; D009154:Mutation; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development
D011506:Proteins; D014450:Electron Transport Complex III