Arabidopsis micro-RNA biogenesis through Dicer-like 1 protein functions
Arabidopsis micro-RNA biogenesis through Dicer-like 1 protein functions
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DOI：
10.1073/pnas.0403115101
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发表时间：
2004-08-24
影响因子：
11.1
通讯作者：
Watanabe, Y
中科院分区：
文献类型：
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作者：
Kurihara, Y;Watanabe, Y
微小RNA（micro-RNAs，miRNAs）是一类长度为18-25 nt的非编码小RNA，在转录后水平负调控与之互补的mRNA。先前的研究表明，一些RNase III样酶，如Drosha和Dicer，已知参与动物中的miRNA生物合成。然而，植物miRNA生物合成的机制仍然知之甚少。本文对拟南芥miR 163基因的生物合成过程进行了研究。结果显示，两种类型的miR 163初级转录本（pri-miR 163 s）是由RNA聚合酶11从单个基因转录的，并且miR 163的生物合成需要至少三个由RNase III样酶以21 nt-长的间隔切割步骤。第一步是从pri-miR 163到长miR 163前体（pre-miR 163），第二步是从长pre-miR 163到短pre-miR 163，最后一步是从短pre-miR 163到成熟miR 163和残余物。有趣的是，在这个过程中，释放了包括miR 163在内的四种小RNA。通过使用dc/1突变体，证明了拟南芥Dicer同源物Dicer样1（DCL 1）催化至少第一和第二切割步骤，并且DCL 1的双链RNA结合结构域参与切割位点的定位。我们的结果是直接证据，表明DCL 1参与了初级和前体miRNA的加工。
Micro-RNAs (miRNAs) are small, noncoding RNAs of 18-25 nt in length that negatively regulate their complementary mRNAs at the posttranscriptional level. Previous work has shown that some RNase III-like enzymes such as Drosha and Dicer are known to be involved in miRNA biogenesis in animals. However, the mechanism of plant miRNA biogenesis still remains poorly understood. In this article, the process of Arabidopsis miR163 biogenesis was examined. The results revealed that two types of miR163 primary transcripts (pri-miR163s) are transcribed from a single gene by RNA polymerase 11 and that miR163 biogenesis requires at least three cleavage steps by RNase III-like enzymes at 21-nt-long intervals. The first step is from pri-miR163 to long miR163 precursor (pre-miR163), the second step is from long pre-miR163 to short pre-miR163, and the last step is from short pre-miR163 to mature miR163 and the remnant. It is interesting that, during the process, four small RNAs including miR163 are released. By using dc/1 mutants, it was demonstrated that Arabidopsis Dicer homologue Dicer-like 1 (DCL1) catalyzes at least the first and second cleavage steps and that double-stranded RNA-binding domains of DCL1 are involved in positioning of the cleavage sites. Our result is direct evidence that DCL1 is involved in processing of pri- and pre-miRNA.