YDL142c encodes cardiolipin synthase (Cls1p) and is non-essential for aerobic growth of Saccharomyces cerevisiae.

The unassigned open reading frame YDL142c was identified to code for cardiolipin synthase, Cls1p. A cls1 deletion strain is viable on glucose, galactose, ethanol, glycerol and lactate containing media, although the growth rate on non-fermentable carbon sources is decreased. Mitochondria of the cls1 mutant are devoid of cardiolipin but accumulate the cardiolipin precursor phosphatidylglycerol when grown on non-fermentable carbon sources. Specific activity of phosphatidylglycerolphosphate synthase in cls1 is reduced to 30-75% of the wild-type level. Amounts of mitochondrial cytochromes and activity of cytochrome c oxidase, however, are not affected in the cls1 deletion strain. Collectively, these data indicate that cardiolipin is not essential for aerobic growth of Saccharomyces cerevisiae.