Fig. 5

Splicing events in the calA gene in M. alpina and transgenic A. niger tJMW06. A Structure of the full-length 20 kb calA gene. The gene is disrupted by six introns. B Splicing pattern of natively expressed calA in M. alpina and heterologously expressed calA in A. niger tJMW06. Both strains were cultivated under inducing conditions (M. alpina in MEP medium, A. niger tJMW06 in AMM with doxycycline). Genomic (gDNA) and cDNA served as templates for diagnostic PCRs spanning the intron in a housekeeping gene (actB or gpdA, respectively) or individually spanning the six introns of calA. Expected fragment sizes are indicated. C MS profile at m/z 768.44 [M + H]⁺ of the induced cultures from M. alpina (upper lane) and A. niger tJMW06 (lower lane). The indicated titer of calpinactam is normalized to the fungal dry weight (calculated from three replicates)