BMH-21 inhibits RNA polymerase I transcription cycle and rDNA occupancy

The objective of this study was to determine the effect of a small-molecule Pol I inhibitor, BMH-21, on rRNA synthesis in vivo. NET-seq was performed to determine the Pol I occupancy after BMH-21 treatment, as compared to vehicle-treatment (phosphate buffer control). Our findings suggest that BMH-21 treatment reduces Pol I occupancy on the rDNA template. Additionally, BMH-21 induces repositioning of Pol I in AT-rich rDNA regions that are directly upstream from GC-rich regions. This study suggests that BMH-21 is a powerful inhibitor of transcription by Pol I, and gives a potential mechanism of action for this inhibitor in vivo.