Identification and characterization of the asperthecin gene cluster of Aspergillus nidulans.
The sequencing of Aspergillus genomes has revealed that the products of a large number of secondary metabolism pathways have not yet been identified. This is probably because many secondary metabolite gene clusters are not expressed under normal laboratory culture conditions. It is, therefore, important to discover conditions or regulatory factors that can induce the expression of these genes. We report that the deletion of sumO, the gene that encodes the small ubiquitin-like protein SUMO in A. nidulans, caused a dramatic increase in the production of the secondary metabolite asperthecin and a decrease in the synthesis of austinol/dehydroaustinol and sterigmatocystin. The overproduction of asperthecin in the sumO deletion mutant has allowed us, through a series of targeted deletions, to identify the genes required for asperthecin synthesis. The asperthecin biosynthesis genes are clustered and include genes encoding an iterative type I polyketide synthase, a hydrolase, and a monooxygenase. The identification of these genes allows us to propose a biosynthetic pathway for asperthecin.
Szewczyk
Edyta
E
Department of Molecular Genetics, Ohio State University, 484 West 12th Avenue, Columbus, Ohio 43210, USA.
Chiang
Yi-Ming
YM
Oakley
C Elizabeth
CE
Davidson
Ashley D
AD
Wang
Clay C C
CC
Oakley
Berl R
BR
D001233:Aspergillus nidulans / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D053898:Biosynthetic Pathways / Q000235:genetics*; D003593:Cytoplasm / Q000737:chemistry; D005656:Fungal Proteins / Q000235:genetics; D017353:Gene Deletion; D005800:Genes, Fungal; D006867:Hydrolases / Q000235:genetics; D006899:Mixed Function Oxygenases / Q000235:genetics; D015394:Molecular Structure; D005810:Multigene Family; D009183:Mycotoxins / Q000096:biosynthesis*; D048630:Polyketide Synthases / Q000235:genetics; D025842:SUMO-1 Protein / Q000235:genetics
D005656:Fungal Proteins; D009183:Mycotoxins; D025842:SUMO-1 Protein; D048630:Polyketide Synthases; D006899:Mixed Function Oxygenases; D006867:Hydrolases