%0 Journal Article %A O'Callaghan, J. %A Caddick, M. X. %A Dobson, A. D. W. %T A polyketide synthase gene required for ochratoxin A biosynthesis in Aspergillus ochraceus %D 2003 %J Microbiology, %V 149 %N 12 %P 3485-3491 %@ 1465-2080 %R https://doi.org/10.1099/mic.0.26619-0 %K OTA, ochratoxin A %K SSH-PCR, suppression subtractive hybridization PCR %K PKS, polyketide synthase %I Microbiology Society, %X Ochratoxin A is an important nephrotoxic and nephrocarcinogenic mycotoxin, produced by Aspergillus ochraceus as a polyketide-derived secondary metabolite. A portion of a putative polyketide synthase gene (pks) involved in the biosynthesis of this mycotoxin was cloned by using a suppression subtractive hybridization PCR-based approach. The predicted amino acid sequence of the 1·4 kb clone shared 28–35 % identity to acyl transferase regions from fungal polyketide synthases found in the databases. Based on reverse transcription PCR studies, the pks gene is expressed only under ochratoxin A permissive conditions and only during the early stages of the mycotoxin synthesis. A mutant in which the pks gene has been interrupted cannot synthesize ochratoxin A. This report is the first of the cloning and characterization of a gene involved in ochratoxin A biosynthesis. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.26619-0