A polyketide synthase gene required for ochratoxin A biosynthesis in Aspergillus ochraceus.
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.
O'Callaghan
J
J
Department of Microbiology, University College Cork, National University of Ireland Cork, Cork, Ireland.
Caddick
M X
MX
School of Biological Sciences, University of Liverpool, Liverpool, UK.
Dobson
A D W
ADW
Department of Microbiology, University College Cork, National University of Ireland Cork, Cork, Ireland.
D000595:Amino Acid Sequence; D001235:Aspergillus ochraceus / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D004271:DNA, Fungal / Q000235:genetics; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D009793:Ochratoxins / Q000096:biosynthesis*; D016133:Polymerase Chain Reaction / Q000379:methods; D017386:Sequence Homology, Amino Acid
D004271:DNA, Fungal; D009097:Multienzyme Complexes; D009793:Ochratoxins; C025589:ochratoxin A