FIG 6.

BbHapX contributes to transcription of BbOle1. (A) Transcription activity of the BbOle1 promoter. The green fluorescent protein (GFP) gene was under the control of the BbOle1 promoter. The hybrid DNA fragment was transformed into the WT and ΔBbHapX mutant strains. The green signals and mycelial morphology were recorded under the fluorescent and bright field (BF), respectively. There is a significant difference in fluorescence intensity between the WT and ΔBbHapX mutant strains (t test). (B) Gel shift assay for the binding activity of BbHapX with the promoter of BbOle1. The soluble BbHapX was prepared by the heterogenous expression of a hybrid gene, BbHapX::Thioredoxin. A 20-μl reaction system contained the promoter DNA (100 ng) and various proteins (0.3 to 2.7 μg). The DNA-protein complex was resolved in a 6% polyacrylamide gel. The shifted DNA bands were visualized by ethidium bromide stain. Thioredoxin (THX) protein was used as a control to examine whether the fusion protein tag bound to the promoter.