Isolation and characterization of a gene from Aspergillus parasiticus associated with the conversion of versicolorin A to sterigmatocystin in aflatoxin biosynthesis
Article Abstract:
An Aspergillus parasiticus cosmid genomic library was screened fora complementary gene for an A. parasiticus mutant deficient in the conversion of versicolorin A to sterigmatocystin, an aflatoxin biosynthetic step. The screening procedure resulted in the isolation of a gene, designated ver-1, which complemented the deficient mutant. Sequence analysis revealed similarities in conserved sequences of reductases and dehydrogenases involved in modification of ring structure. Homology searches showed that the ver-1 geneproduct is very similar to Steptomyces ketoreductases.
Publication Name: Applied and Environmental Microbiology
Subject: Biological sciences
ISSN: 0099-2240
Year: 1992
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avnA, a gene encoding a cytochrome P-450 monoxygenase, is involved in the conversion of averantin to averufin in aflatoxin biosynthesis in Aspergillus parasiticus
Article Abstract:
The avnA gene from the filamentous fungi Aspergillus flavus, corresponding to one of the two transcripts found between the ver-1 and omtA genes on the gene cluster involved in the aflatoxin biosynthetic pathway, was sequenced. Its nucleotide sequence has a coding region for a protein of 495 amino acids with a molecular mass of 56.3 kDa. The gene is composed of three exons and two introns. Disruption of the avnA gene in the wild-type aflatoxigenic A. parasiticus strain produced a nonaflatoxigenic mutant which accumulated a bright yellow pigment.
Publication Name: Applied and Environmental Microbiology
Subject: Biological sciences
ISSN: 0099-2240
Year: 1997
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Regulated expression of the nor-1 and ver-1 genes associated with aflatoxin biosynthesis
Article Abstract:
The accumulation of RNA transcripts for the nor-1 and ver-1 genes, which are associated with aflatoxin biosynthesis in the fungus Aspergillus parasiticus, was studied before and during aflatoxin production. It was observed that RNA transcripts for these genes do not accumulate until near the end of trophophase. The results suggest that aflatoxin biosynthesis is partly regulated by the accumulation of the nor-1 and ver-1 transcripts.
Publication Name: Applied and Environmental Microbiology
Subject: Biological sciences
ISSN: 0099-2240
Year: 1993
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