Characterization of the promoter for the gene encoding the aflatoxin biosynthetic pathway regulatory protein AFLR

Biochim Biophys Acta. 1999 Mar 19;1444(3):412-7. doi: 10.1016/s0167-4781(99)00022-6.

Abstract

Most genes in the aflatoxin biosynthetic pathway in Aspergillus parasiticus are regulated by the binuclear zinc cluster DNA-binding protein AFLR. The aflR promoter was analyzed in beta-glucuronidase reporter assays to elucidate some of the elements involved in the gene's transcription control. Truncation at 118 bp upstream of the translational start site increased promoter activity 5-fold, while truncation at -100 reduced activity about 20-fold. These findings indicate the presence of an important positive regulatory element between -100 and -118 and a negative regulatory region further upstream. Electrophoretic mobility shift assays on nuclear extracts from A. parasiticus induced for aflatoxin expression suggest that AFLR and another, possibly more abundant, protein bind to the -100/-118 region. Another protein binds to a sequence at position -159 to -164 that matches the consensus binding site for the transcription factor involved in pH-dependent gene regulation, PACC.

MeSH terms

  • Aflatoxins / biosynthesis*
  • Aflatoxins / genetics
  • Aspergillus / genetics*
  • Base Sequence
  • DNA-Binding Proteins / genetics*
  • Fungal Proteins*
  • Gene Expression Regulation / genetics*
  • Molecular Sequence Data
  • Promoter Regions, Genetic
  • Sequence Deletion
  • Transcription Factors*
  • Transcription, Genetic

Substances

  • AFLR protein, Aspergillus
  • Aflatoxins
  • DNA-Binding Proteins
  • Fungal Proteins
  • Transcription Factors