Complementation of Hyponastic Leaves1 by Double-Strand RNA-Binding Domains of Dicer-Like1 in Nuclear Dicing Bodies
Complementation of Hyponastic Leaves1 by Double-Strand RNA-Binding Domains of Dicer-Like1 in Nuclear Dicing Bodies
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DOI：
10.1104/pp.113.219071
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发表时间：
2013-09-01
期刊：
影响因子：
7.4
通讯作者：
Fang, Yuda
中科院分区：
文献类型：
--
作者：
Liu, Qi;Yan, Qingqing;Fang, Yuda
microRNA（miRNAs）是一类小的调控RNA，几乎在所有的真核生物中都存在。拟南芥（Arabidopsis thaliana）的miRNAs主要由核糖核酸酶III样酶DICER-LIKE 1（DCL 1）及其特异性配偶体HYPONASTIC leaves 1（HYL 1）（一种双链RNA结合蛋白）从初级miRNAs（pri-miRNAs）加工而成，这两种酶都含有两个双链RNA结合结构域（dsRBD）。这些dsRBD是miRNA加工所必需的，但它们的功能尚不清楚。在这里，我们报告了DCL 1的两个dsRBD（DCL 1-D1 D2），以及在某种程度上第二个dsRBD（DCL 1-D2），补充了hyl 1突变体，但不是DCL 1的第一个dsRBD（DCL 1-D1）。DCL 1-D1弥散分布在整个核质中，而DCL 1-D2和DCL 1-D1 D2集中在DCL 1和HYL 1共定位的核切割体中。我们进一步表明，蛋白质-蛋白质相互作用主要由DCL 1-D2介导，而DCL 1-D1在pri-miRNAs的结合中起主要作用。这些结果表明DCL 1的C-末端dsRBD和HYL 1的N-末端dsRBD之间的平行作用，并支持通过微处理器的功能不同的dsRBD将拟南芥pri-miRNAs募集到切割体以精确加工植物pri-miRNAs的模型。
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.