biostudies-literatureLiang CGuangdong Innovative and Entrepreneurial Research Team ProgramFoundation for the National Institutes of HealthNational Natural Science Foundation of ChinaChina Postdoctoral Science FoundationNIGMS NIH HHS1217https://www.ebi.ac.uk/biostudies/studies/S-EPMC8904849biostudies-literatureUnknown13(1)MicroRNAs (miRNAs) play crucial roles in gene expression regulation through RNA cleavage or translation repression. Here, we report the identification of an evolutionarily conserved WD40 domain protein as a player in miRNA biogenesis in Arabidopsis thaliana. A mutation in the REDUCTION IN BLEACHED VEIN AREA (RBV) gene encoding a WD40 domain protein led to the suppression of leaf bleaching caused by an artificial miRNA; the mutation also led to a global reduction in the accumulation of endogenous miRNAs. The nuclear protein RBV promotes the transcription of MIR genes into pri-miRNAs by enhancing the occupancy of RNA polymerase II (Pol II) at MIR gene promoters. RBV also promotes the loading of miRNAs into AGO1. In addition, RNA-seq revealed a global splicing defect in the mutant. Thus, thisNature communicationsArabidopsis RBV is a conserved WD40 repeat protein that promotes microRNA biogenesis and ARGONAUTE1 loading.PMC8904849GM129373318702872014ZT05S078)2015M582402R01 GM12937331701112Liang CMo BCai QLan TLi SGao LYou CCao DWang FXu CChen XZhang BfalseArabidopsis RBV is a conserved WD40 repeat protein that promotes microRNA biogenesis and ARGONAUTE1 loading.MicroRNAs (miRNAs) play crucial roles in gene expression regulation through RNA cleavage or translation repression. Here, we report the identification of an evolutionarily conserved WD40 domain protein as a player in miRNA biogenesis in Arabidopsis thaliana. A mutation in the REDUCTION IN BLEACHED VEIN AREA (RBV) gene encoding a WD40 domain protein led to the suppression of leaf bleaching caused by an artificial miRNA; the mutation also led to a global reduction in the accumulation of endogenous miRNAs. The nuclear protein RBV promotes the transcription of MIR genes into pri-miRNAs by enhancing the occupancy of RNA polymerase II (Pol II) at MIR gene promoters. RBV also promotes the loading of miRNAs into AGO1. In addition, RNA-seq revealed a global splicing defect in the mutant. Thus, this2022-01-01T00:00:00Z2022 Mar2025-04-19T13:02:17.011Z2025-04-19T13:02:17.011ZS-EPMC89048493526056810.1038/s41467-022-28872-x