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Aspergillus westerdijkiae polyketide synthase gene “aoks1” is involved in the biosynthesis of ochratoxin A

Bacha, Nafees and Atoui, Ali and Mathieu, Florence and Liboz, Thierry and Lebrihi, Ahmed Aspergillus westerdijkiae polyketide synthase gene “aoks1” is involved in the biosynthesis of ochratoxin A. (2009) Fungal Genetics and Biology, vol. 46 (n° 1). pp. 77-84. ISSN 1087-1845

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Official URL: http://dx.doi.org/10.1016/J.FGB.2008.09.015

Abstract

OchratoxinA (OTA) is a potential nephrotoxic, teratogenic, immunogenic, hepatotoxic and carcinogenic mycotoxin, produced by Aspergillus westerdijkiae NRRL 3174. Herein we describe the characterization of a putative OTA-polyketide synthasegene “aoks1”, cloned by using gene walking approach. The predicted amino acid sequence of the 2 kb clone display 34–60% similarities to different polyketide synthasegenes including lovastatine biosynthesis gene “lovb” in A. terreus, compactin biosynthesis gene “mlcA” in Penicillium citrinum and OTA biosynthesis gene “otapksPN” in P. nordicum. Based on the reverse transcription PCR and kinetic secondary metabolites production studies, aoks1 expression was found to be associated with OTA biosynthesis. Further a mutant, in which the aoks1gene was inactivated by Escherichia coli hygromycin B phosphotransferase gene, lost the capacity to produce OTA, but still producing mellein. To our knowledge this report describes for the first time characterization of a gene involved in OTA biosynthesis, with the information about mellein which was proposed in the literature to be an intermediate OTA. This study also suggests that aoks1 may be the second polyketide synthase gene required for OTA biosynthesis in A. westerdijkiae NRRL 3174.

Item Type:Article
Additional Information:Thanks to Elsevier editor. The definitive version is available at http://www.sciencedirect.com The original PDF of the article can be found at : http://www.sciencedirect.com/science/article/pii/S1087184508002016
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS
Other partners > National Council For Scientific Research Lebanon - CNRS (LEBANON)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT
Université de Toulouse > Université Paul Sabatier-Toulouse III - UPS
Laboratory name:
Laboratoire de Génie Chimique - LGC (Toulouse, France) - Bioprocédés et systèmes microbiens (BioSyM)
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Deposited By: Audrey LEFEVRE

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