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Applied Microbiology and Biotechnology

, Volume 55, Issue 5, pp 585–589 | Cite as

Pre-termination in aflR of Aspergillus sojae inhibits aflatoxin biosynthesis

  •  K. Matsushima
  •  P.-K. Chang
  •  J. Yu
  •  K. Abe
  •  D. Bhatnagar
  •  T. Cleveland
Original Paper

Abstract.

The aflR gene product is the main transcriptional regulator of aflatoxin biosynthesis in Aspergillus parasiticus and Aspergillus flavus. Although A. sojae strains do not produce aflatoxins, they do have an aflR homologue. When compared with the aflR of A. parasiticus, the A. sojae gene contains two mutations: an HAHA motif and a premature stop codon. To investigate the functionality of the A. sojae aflR gene product, we used a GAL4 one-hybrid system in yeast. The transcription-activating activity of AflR from A. sojae was 15% of that from A. parasiticus. The introduction of an additional aflR from A. sojae into an A. parasiticus strain did not affect aflatoxin productivity. A hybrid aflR comprising the amino-terminal region of A. sojae aflR and the carboxy-terminal region of A. parasiticus aflR suppressed the effect associated with pre-termination of the A. sojae AflR. We conclude that the premature stop codon of the A. sojae aflR is the key to its functionality and leads to prevention of aflatoxin biosynthesis through loss of the transcription of aflatoxin biosynthesis-related genes.

Keywords

Codon Gene Product Aspergillus Transcriptional Regulator Aflatoxin 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag 2001

Authors and Affiliations

  •  K. Matsushima
    • 1
  •  P.-K. Chang
    • 2
  •  J. Yu
    • 2
  •  K. Abe
    • 1
  •  D. Bhatnagar
    • 2
  •  T. Cleveland
    • 2
  1. 1.Research and Development Division, Kikkoman Corporation, 399 Noda, Noda-City, Chiba 278–0037, Japan
  2. 2.Southern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 1100 Robert E. Lee Boulevard, New Orleans, LA 70124, USA

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