Cloning and characterization of the POX2 gene in Candida maltosa.

To study the function of acyl-CoA oxidase in an n-alkane-assimilating yeast, Candida maltosa, we isolated the POX2 gene which is a member of the acyl-CoA oxidase gene family. POX2 had a 2172-bp open reading frame (ORF) encoding an approx. 84-kDa polypeptide (724 amino acids (aa)) and was contiguous to POX4, another member of the acyl-CoA oxidase gene family on the same chromosomal DNA in a convergent arrangement. Northern blot analysis revealed that the expression of POX2 was induced in cells grown on oleic acid, n-tetradecanol and n-tetradecane. By using a gene-disruption technique, we constructed strains (termed P2DD and P4DD) in which both alleles of POX2 and POX4 were disrupted. The P2DD strain was normal in assimilation of various hydrophobic carbon sources, such as n-tetradecane, n-tetradecanol and oleic acid. In contrast, the P4DD strain was defective in its ability to grow on such hydrophobic carbon sources.