Abstract
For decades, microRNAs (miRNAs) have been canonically viewed as post-transcriptional repressors. We discovered extensive binding of microRNAs to chromatin-associated RNAs (caRNAs) and uncovered an N (6) -methyladenosine (m (6) A)-dependent transcriptional activation mechanism of microRNAs. We show that m (6) A-binding proteins FXR1/2 anchor AGO1/2 at m (6) A-marked caRNAs, where AAGUGC-seed microRNAs function as guide RNAs to direct AGO positioning. This dual anchoring stabilizes the AGO-microRNA/FXR-m (6) A complex at specific loci, which in turn recruits the ATP-dependent chromatin remodeler SMARCA4 (BRG1) to promote local chromatin opening and TET1 for DNA demethylation, respectively. Together, these coordinated activities establish a transcriptionally permissive chromatin environment, enhancing accessibility and transcription across hundreds of genes in diverse cell types. Beyond the AAGUGC-seed family, additional microRNAs and siRNAs also enhance transcription, suggesting that caRNA binding and transcriptional activation may represent a broader property of small RNAs.