A. fumigatus produces many toxic secondary metabolites including peptide derivatives and indole alkaloids Gliotoxin Tryprostatins Fumitremorgens Fumigaclavines Can we identify the gene clusters responsible?
Gardiner et al. Mol. Microbiol. (2004) Sirodesmin cluster of Leptophaeria maculans Sirodesmin Gliotoxin Putative A. fumigatus gliotoxin cluster identified in genome by homology: Includes 2 module NRPS
Gene typeA. oryzaeA. fumigatusA. nidulans PKS301427 NRPS1814 FAS516 Sesquiterpene cyclase 1(1) DMATS272 DMATS hits probably reflect a variety of prenyltransferases - add dimethylallyl side chain to a variety of compounds
monooxygenase- related protein Hypothetical protein NADP- dehydrogenase Conserved hypothetical protein Pisatin demethylase, putative Putative dimethyl- allyl-tryptophan- synthetase Oxidoreductase Cp ox2 Cytochrome P450, monooxygenase Acetyl transferase Catalase Dimethylallyl trryptophan synthetase Oxidoreductase Cp ox1 Conservedd Hypothetical protein DMATII DMATII 72. M19886 shows 52 % identity with Claviceps purpurea DMAT gene. DMATIII 72. m19881 shows 30 % identity with Claviceps purpurea DMAT gene. Oxidoreductase 72.m19888 has best hit (43%) with C. purpurea ox1 NADPH dehydrogenase 19877 (cpox3?), one of a family, best hit with Claviceps, 57%. Catalase 19885, 72% with Claviceps cluster Short chain dehydrogenase, 19882, 60% with Claviceps cluster DMATIII
Deletion of DMATSII (= dmaW) leads to loss of fumigaclavine C Coyle & Panaccione 2005
alb-1 (=wA) Melanin cluster in A. fumigatus This cluster is not conserved in Ana/Aoa More like N. crassa melanin genes wA is in a conserved syntenic region in both species deletions do affect spore pigment colour pigment biosynthesis pathway may be different in Afu1
Any other orthologues amonst the PKS genes? Phylogeny done by Resham Kulkani at TIGR Using KS domain of PKS/Fatty Acid Synthase
PKS for aflatoxin in 2 species only
Possible orthologues amongst unknown PKS?
Hybrid PKS/NRPS KS-AT-CON-AMP-PP In all 3 species, but not really orthologues?
Conclusions Few true orthologues across the genus Aspergillus Each species has its own repertoire Orthologues often found in less closely related species Gene/product relationship requires functional analysis in most cases
Secondary metabolism – University of Sheffield Hala Mohamed Shubha Maiya Jackie Price David Keszenman-Pereyra Bioinformatics TIGR Broad Institute AIST-CBRC University of Tokyo Chemistry – University of Tubingen Alexander Grundmann Shuming Li