Many secondary metabolism pathways of A. nidulans and A. fumigatus are dependent on the pptA gene product for post-translational modification of non-ribosomal peptide synthetases or polyketide synthases by addition of a 4’-phosphopantetheine cofactor. Inspection of the genome sequences of A. nidulans and A. fumigatus identified a second putative pantothenyl transferase termed pptB. Deletion of pptB from A. fumigatus resulted in stable heterokaryons, and permitted the identification of a deletion phenotype as microcolonies, capable of only very slow growth. When the gene was placed under control of the PalcA promoter, repression led to slow growing colonies. GFP localisation showed the presence of the gene product within the mitochondria. Taken together, our data suggest that pptB is an orthologue of the yeast gene PPT2. PPT2 is known to encode a PPTase specific for a small mitochondrial acyltransferase Acp1p. An orthologue of Acp1p has been previously investigated in N. crassa, and is a component of mitochondrial complex I. While yeast lacks complex I, Acp1p is involved in lipoic acid biosynthesis within the mitochondria. Putative orthologues of Acp1p are also present in A. fumigatus and A. nidulans.
Full conference title:
9th EUROPEAN CONFERENCE ON FUNGAL GENETICS
- ECFG 9th (2008)