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. 2005 Dec;71(12):8963-5.
doi: 10.1128/AEM.71.12.8963-8965.2005.

An aflatoxin biosynthesis cluster gene encodes a novel oxidase required for conversion of versicolorin a to sterigmatocystin

Kenneth C Ehrlich  1 , Beverly Montalbano, Stephen M Boué, Deepak Bhatnagar
Affiliations

An aflatoxin biosynthesis cluster gene encodes a novel oxidase required for conversion of versicolorin a to sterigmatocystin

Kenneth C Ehrlich et al. Appl Environ Microbiol. 2005 Dec.

Abstract

Disruption of the aflatoxin biosynthesis cluster gene aflY (hypA) gave Aspergillus parasiticus transformants that accumulated versicolorin A. This gene is predicted to encode the Baeyer-Villiger oxidase necessary for formation of the xanthone ring of the aflatoxin precursor demethylsterigmatocystin.

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Figures

FIG. 1.
FIG. 1.
Preparation and characterization of aflY disruptant mutants of A. parasiticus. (A) Expected results of double-crossover insertion of pAFLY XhoI fragment into BN009E DNA. X, XhoI site. The shaded region represents the niaD cassette used as the selection marker for fungal transformation. Large arrows indicate direction of transcription. (B) Silica gel thin-layer chromatography of acetone extracts of mycelia from transformants. Lane 1, extract of mycelia from wild-type (WT) fungi. Other lanes are extracts from transformants. Plates were developed with toluene-ethylene acetate-acetic acid (80:30:4, vol/vol/vol). stds, standards. (C) Southern blot analysis of XhoI-digested DNAs from an aflY disruptant (H2, lane 2 of Fig. 1B) and untransformed BN009E with a 32P-labeled 829-bp portion of aflY as the probe. (D) RT-PCR of RNAs from hypA disruptant H2 and untransformed BN009E. Oligonucleotides used for RT-PCR hybridized to coding regions of the aflY and aflX genes.
FIG. 2.
FIG. 2.
Possible pathway for conversion of VA to dimethyl ST. Structures in brackets are hypothetical intermediates as proposed by Henry and Townsend (9).
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References

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