DRB1 as a mediator between transcription and microRNA processing

Abstract

7DRB1 (HYL1) is a double-stranded RNA binding protein involved in miRNA processing in plants. 8 It is a core component of the Microprocessor complex and enhances the efficiency and 9 precision of miRNA processing by DCL1 protein. In this work, we report a novel function of 10 DRB1 protein in the transcription of MIR genes. DRB1 co-localizes with RNA Polymerase II and 11 affects its distribution along MIR genes. Moreover, proteomic experiments revealed that 12 DRB1 protein interacts with many transcription factors. Finally, we show that the action of 13 DRB1 is not limited to MIR genes as it impacts expression of many other genes, majority of 14 which are involved in plant response to light. These discoveries add DRB1 as another player 15 of gene regulation at transcriptional level, independent of its role in miRNA biogenesis. 16