• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of geneticsGeneticsCurrent IssueInformation for AuthorsEditorial BoardSubscribeSubmit a Manuscript
Genetics. Oct 1999; 153(2): 715–720.
PMCID: PMC1460771

Aspergillus nidulans mutants defective in stc gene cluster regulation.

Abstract

The genes involved in the biosynthesis of sterigmatocystin (ST), a toxic secondary metabolite produced by Aspergillus nidulans and an aflatoxin (AF) precursor in other Aspergillus spp., are clustered on chromosome IV of A. nidulans. The sterigmatocystin gene cluster (stc gene cluster) is regulated by the pathway-specific transcription factor aflR. The function of aflR appears to be conserved between ST- and AF-producing aspergilli, as are most of the other genes in the cluster. We describe a novel screen for detecting mutants defective in stc gene cluster activity by use of a genetic block early in the ST biosynthetic pathway that results in the accumulation of the first stable intermediate, norsolorinic acid (NOR), an orange-colored compound visible with the unaided eye. We have mutagenized this NOR-accumulating strain and have isolated 176 Nor(-) mutants, 83 of which appear to be wild type in growth and development. Sixty of these 83 mutations are linked to the stc gene cluster and are likely defects in aflR or known stc biosynthetic genes. Of the 23 mutations not linked to the stc gene cluster, 3 prevent accumulation of NOR due to the loss of aflR expression.

Full Text

The Full Text of this article is available as a PDF (155K).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Cardwell K, Miller JD. Mycotoxins in foods in Africa. Nat Toxins. 1996;4(3):103–107. [PubMed]
  • Chang PK, Cary JW, Bhatnagar D, Cleveland TE, Bennett JW, Linz JE, Woloshuk CP, Payne GA. Cloning of the Aspergillus parasiticus apa-2 gene associated with the regulation of aflatoxin biosynthesis. Appl Environ Microbiol. 1993 Oct;59(10):3273–3279. [PMC free article] [PubMed]
  • Fernandes M, Keller NP, Adams TH. Sequence-specific binding by Aspergillus nidulans AflR, a C6 zinc cluster protein regulating mycotoxin biosynthesis. Mol Microbiol. 1998 Jun;28(6):1355–1365. [PubMed]
  • Hicks JK, Yu JH, Keller NP, Adams TH. Aspergillus sporulation and mycotoxin production both require inactivation of the FadA G alpha protein-dependent signaling pathway. EMBO J. 1997 Aug 15;16(16):4916–4923. [PMC free article] [PubMed]
  • Kelkar HS, Skloss TW, Haw JF, Keller NP, Adams TH. Aspergillus nidulans stcL encodes a putative cytochrome P-450 monooxygenase required for bisfuran desaturation during aflatoxin/sterigmatocystin biosynthesis. J Biol Chem. 1997 Jan 17;272(3):1589–1594. [PubMed]
  • Keller NP, Hohn TM. Metabolic pathway gene clusters in filamentous fungi. Fungal Genet Biol. 1997 Feb;21(1):17–29. [PubMed]
  • Lee L, Bennett JW, Goldblatt LA, Lundin RE. Norsolorinic acid from a mutant strain of Aspergillus parasiticus. J Am Oil Chem Soc. 1971 Feb;48(2):93–94. [PubMed]
  • Müller WH, Bovenberg RA, Groothuis MH, Kattevilder F, Smaal EB, Van der Voort LH, Verkleij AJ. Involvement of microbodies in penicillin biosynthesis. Biochim Biophys Acta. 1992 Apr 22;1116(2):210–213. [PubMed]
  • Payne GA, Nystrom GJ, Bhatnagar D, Cleveland TE, Woloshuk CP. Cloning of the afl-2 gene involved in aflatoxin biosynthesis from Aspergillus flavus. Appl Environ Microbiol. 1993 Jan;59(1):156–162. [PMC free article] [PubMed]
  • PONTECORVO G, ROPER JA, HEMMONS LM, MACDONALD KD, BUFTON AWJ. The genetics of Aspergillus nidulans. Adv Genet. 1953;5:141–238. [PubMed]
  • Anderson JA, Chung CH, Cho SH. Versicolorin A hemiacetal, hydroxydihydrosterigmatocystin, and aflatoxin G2 alpha reductase activity in extracts from Aspergillus parasiticus. Mycopathologia. 1990 Jul;111(1):39–45. [PubMed]
  • Schroeder HW, Hein H., Jr Aflatoxins: production of the toxins in vitro in relation to temperature. Appl Microbiol. 1967 Mar;15(2):441–445. [PMC free article] [PubMed]
  • Wieser J, Lee BN, Fondon J w, 3rd, Adams TH. Genetic requirements for initiating asexual development in Aspergillus nidulans. Curr Genet. 1994 Dec;27(1):62–69. [PubMed]
  • Bressac B, Kew M, Wands J, Ozturk M. Selective G to T mutations of p53 gene in hepatocellular carcinoma from southern Africa. Nature. 1991 Apr 4;350(6317):429–431. [PubMed]
  • Yu JH, Leonard TJ. Sterigmatocystin biosynthesis in Aspergillus nidulans requires a novel type I polyketide synthase. J Bacteriol. 1995 Aug;177(16):4792–4800. [PMC free article] [PubMed]
  • Brown DW, Adams TH, Keller NP. Aspergillus has distinct fatty acid synthases for primary and secondary metabolism. Proc Natl Acad Sci U S A. 1996 Dec 10;93(25):14873–14877. [PMC free article] [PubMed]
  • Yu JH, Butchko RA, Fernandes M, Keller NP, Leonard TJ, Adams TH. Conservation of structure and function of the aflatoxin regulatory gene aflR from Aspergillus nidulans and A. flavus. Curr Genet. 1996 May;29(6):549–555. [PubMed]
  • Brown DW, Yu JH, Kelkar HS, Fernandes M, Nesbitt TC, Keller NP, Adams TH, Leonard TJ. Twenty-five coregulated transcripts define a sterigmatocystin gene cluster in Aspergillus nidulans. Proc Natl Acad Sci U S A. 1996 Feb 20;93(4):1418–1422. [PMC free article] [PubMed]
  • Berse B, Dmochowska A, Skrzypek M, Wegleński P, Bates MA, Weiss RL. Cloning and characterization of the ornithine carbamoyltransferase gene from Aspergillus nidulans. Gene. 1983 Nov;25(1):109–117. [PubMed]

Articles from Genetics are provided here courtesy of Genetics Society of America

Formats:

Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...

Links

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...