FIG 6.

Transcriptional activation of solanapyrone cluster genes by the sol4 gene. The expression levels of the solanapyrone cluster genes by the WT strain and the Δsol4 mutant grown on PDA (A) and in the WT strain and two independent sol4-overexpressing strains (4OE2-2 and 4OE6-2) grown in CM broth upon induction with polygalacturonic acid (B) were analyzed by RT-PCR. The expected band sizes of mRNA (lower bands) and pre-mRNA/genomic DNA (gDNA) (upper bands) are indicated (the numbers to the left and right of the gels are in base pairs). Similar results were obtained from three independent experiments. Lanes M, 100-bp DNA ladder. Since all the primer pairs were designed to amplify flanking exons, including one intron, the absence of the upper band in the Actin1 reference gene (A) indicates that there was no genomic DNA contamination.