Fig. 3

Binding and transcriptional analysis of MtrA with avermectin biosynthesis related genes. a Predicted promoters in the avermectin biosynthesis gene cluster. b EMSA analysis of the binding of MtrA to the promoter of avermectin synthesis related genes (lane 1: 50 ng labeled probe, lane 2: 50 ng labeled probe + 3 μg MtrA protein, lane 3: 50 ng labeled probe + 6 μg MtrA protein, lane 4: 50 ng labeled probe + 3 μg MtrA protein + excess unlabeled competing probes). c qRT-PCR results for genes aveA1, aveA2, aveC, aveE, aveA4, orf-1, and aveR within the avermectin biosynthesis cluster. qRT- PCR was performed using S. avermitilis 16S rRNA as a reference gene, resulting in the transcript levels of each gene compared to the reference gene