A role for the RNA-binding protein MOS2 in microRNA maturation in Arabidopsis

Abstract

microRNAs (miRNAs) play important roles in the regulation of gene expression. In Arabidopsis, mature miRNAs are processed from primary miRNA transcripts (pri-miRNAs) by nuclear HYL1/SE/DCL1 complexes that form Dicing bodies (D-bodies). Here we report that an RNA-binding protein MOS2 binds to pri-miRNAs and is involved in efficient processing of pri-miRNAs. MOS2 does not interact with HYL1, SE, and DCL1 and is not localized in D-bodies. Interestingly, in the absence of MOS2, the recruitment of pri-miRNAs by HYL1 is greatly reduced and the localization of HYL1 in D-bodies is compromised. These data suggest that MOS2 promotes pri-miRNA processing through facilitating the recruitment of pri-miRNAs by the Dicing complexes.