Transcription profiling by high throughput sequencing of Arabidopsis mos2-2 mutant seedlings

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 a RNA-binding protein MOS2 bound to pri-miRNAs and was required for their efficient processing. MOS2 did not interact with HYL1, SE, and DCL1 and was not localized in D-bodies. Interestingly, in the absence of MOS2, the recruitment of pri-miRNAs by HYL1 was greatly reduced and the localization of HYL1 in D-bodies was compromised. These data suggest that MOS2 facilitates pri-miRNA processing through facilitating the recruitment of pri-miRNAs by the Dicing complexes. Examination of gene expression profiles in Col-0 and mos2-2 plants by deep sequencing