Sterigmatocystin (ST) is a carcinogenic polyketide produced by several filamentous fungi including Aspergillus nidulans. Expression of ST biosynthetic genes (stc genes) requires activity of a Zn(II)2Cys6 transcription factor, AflR. aflR is transcriptionally and post-transcriptionally regulated by a G-protein/cAMP/protein kinase A (PkaA) signaling pathway involving FlbA, an RGS (regulator of G-p...

Aflatoxins are polyketide-derived secondary metabolites produced by Aspergillus spp. The toxic effects of aflatoxins have adverse consequences for human health and agricultural economics. The aflR gene, a regulatory gene for aflatoxin biosynthesis, encodes a protein containing a zinc-finger DNA-binding motif. AFLR-Protein three-dimensional model was generated using Robetta server. The modeled A...

AFLR, a DNA-binding protein of 444 amino acids, transactivates the expression of aflatoxin biosynthesis genes in Aspergillus parasiticus and Aspergillus flavus, as well as the sterigmatocystin synthesis genes in Aspergillus nidulans. We show here by fusion of various aflR coding regions to the GAL4 DNA-binding coding region that the AFLR carboxyl terminus contained a region that activated GAL1:...

background and purpose: mycotoxins are secondary fungal metabolites with a very high diversity that are produced by some species of aspergillus which frequently leads to contaminate food and agricultural products. recently, elimination of aflatoxin contamination in food and feed has been considered by scientists worldwide. although, the antibacterial and antifungal effects of vitamins as natura...

The aflR gene from Aspergillus parasiticus and Aspergillus flavus may be involved in the regulation of aflatoxin biosynthesis. The aflR gene product, AFLR, possesses a GAL4-type binuclear zinc finger DNA-binding domain. A transformant, SU1-N3 (pHSP), containing an additional copy of aflR, showed increased transcription of aflR and the aflatoxin pathway structural genes, nor-1, ver-1, and omt-1,...

Aflatoxins (AFs) are carcinogenic secondary metabolites of Aspergillus parasiticus. In previous studies, non-toxigenic A. parasiticus sec- (for secondary metabolism negative) variants were generated through serial transfer of mycelia from their toxigenic sec+ (for secondary metabolism positive) parents for genetic and physiological analysis for understanding regulation of AF biosynthesis. Previ...

Aflatoxins are the most potent naturally occurring carcinogens of fungal origin. Biosynthesis of aflatoxin involves the coordinated expression of more than 25 genes. The function of one gene in the aflatoxin gene cluster, aflJ, is not entirely understood but, because previous studies demonstrated a physical interaction between the Zn2Cys6 transcription factor AflR and AflJ, AflJ was proposed to...

Aflatoxin contamination of foods and feeds is a world-wide agricultural problem. Aflatoxin production requires expression of the biosynthetic pathway regulatory gene, aflR, which encodes a Cys6Zn2-type DNA-binding protein. Homologs of aflR from Aspergillus nomius, bombycis, parasiticus, flavus, and pseudotamarii were compared to investigate the molecular basis for variation among aflatoxin-prod...

The filamentous fungus Aspergillus nidulans contains a cluster of 25 genes that encode enzymes required to synthesize a toxic and carcinogenic secondary metabolite called sterigmatocystin (ST), a precursor of the better known fungal toxin aflatoxin (AF). One ST Cluster (stc) gene, aflR, functions as a pathway-specific transcriptional regulator for activation of other genes in the ST pathway. Ho...