A functional homolog of the Saccharomyces cerevisiae HAP2 gene, coding
for one element of a transcriptional activator complex, was cloned fr
om the yeast Kluyveromyces lactis and its nucleotide sequence was dete
rmined, Inactivation of the gene had no significant effect on respirat
ion-dependent growth, suggesting that the HAP2/3/4 complex has no majo
r control over the formation of the mitochondrial respiratory system i
n K. lactis.