... suppression of respiration during hypoxia In the absence of differential regulation of a speci c nuclear gene coding for the subunits of CytOX, changes in the microenvironment of the cell may induce alterations ... modulates the expression of mRNAs for CytOX subunits and also the catalytic activity of the enzyme complex Our results show that the levels of some of the select mitochondrial and nuclear genome encoded ... genes CYC1 and CYC7, which encode iso-1 and iso-2 of yeast cytochrome c, respectively CytOX 5a and CYC1 are coexpressed under aerobic conditions (O2 > 0.5 lM), whereas CytOX 5b and CYC7 are co-expressed...