title: Complementation of HYPONASTIC LEAVES1 by double-strand RNA-binding domains of DICER-LIKE1 in nuclear dicing bodies.
abstract: MicroRNAs (miRNAs) are a class of small regulatory RNAs that are found in almost all of the eukaryotes. Arabidopsis (Arabidopsis thaliana) miRNAs are processed from primary miRNAs (pri-miRNAs), mainly by the ribonuclease III-like enzyme DICER-LIKE1 (DCL1) and its specific partner, HYPONASTIC LEAVES1 (HYL1), a double-strand RNA-binding protein, both of which contain two double-strand RNA-binding domains (dsRBDs). These dsRBDs are essential for miRNA processing, but the functions of them are not clear. Here, we report that the two dsRBDs of DCL1 (DCL1-D1D2), and to some extent the second dsRBD (DCL1-D2), complement the hyl1 mutant, but not the first dsRBD of DCL1 (DCL1-D1). DCL1-D1 is diffusely distributed throughout the nucleoplasm, whereas DCL1-D2 and DCL1-D1D2 concentrate in nuclear dicing bodies in which DCL1 and HYL1 colocalize. We show further that protein-protein interaction is mainly mediated by DCL1-D2, while DCL1-D1 plays a major role in binding of pri-miRNAs. These results suggest parallel roles between C-terminal dsRBDs of DCL1 and N-terminal dsRBDs of HYL1 and support a model in which Arabidopsis pri-miRNAs are recruited to dicing bodies through functionally divergent dsRBDs of microprocessor for accurate processing of plant pri-miRNAs.
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Liu
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Yan
authors.forename: Yin
authors.initials: Y
authors.lastname: Liu
authors.forename: Fang
authors.initials: F
authors.lastname: Hong
authors.forename: Zhenfei
authors.initials: Z
authors.lastname: Sun
authors.forename: Leilei
authors.initials: L
authors.lastname: Shi
authors.forename: Ying
authors.initials: Y
authors.lastname: Huang
authors.forename: Yuda
authors.initials: Y
authors.lastname: Fang
mesh_terms: D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D035683:MicroRNAs; D016601:RNA-Binding Proteins / Q000235:genetics*; D043244:Ribonuclease III / Q000032:analysis / Q000235:genetics* / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; C420966:HYL1 protein, Arabidopsis; D035683:MicroRNAs; D016601:RNA-Binding Proteins; C402383:DCL1 protein, Arabidopsis; D043244:Ribonuclease III