dxy

Lee, Y; Ahn, C; Han, JJ; Choi, H; Kim, J; Yim, J; Lee, J; Provost, P; Radmark, O; Kim, S; Kim, VN  Nature 2003,425(6956)415-419 引用次数 1098

这篇发表于2003年的Nature杂志报道了另一个RNAase III超家族成员Drosha，Drosha剪切pri-miRNA形成pre-miRNA，后者进而被Dicer剪切形成成熟的miRNA。这一发现完善了miRNA形成的分子机制。

【摘要】Hundreds of small RNAs of similar to 22 nucleotides, collectively named microRNAs (miRNAs), have been discovered recently in animals and plants(1-10). Although their functions are being unravelled(1,2,11-13), their mechanism of biogenesis remains poorly understood. miRNAs are transcribed as long primary transcripts (pri-miRNAs) whose maturation occurs through sequential processing events: the nuclear processing of the pri-miRNAs into stem-loop precursors of similar to70 nucleotides (pre-miRNAs), and the cytoplasmic processing of pre-miRNAs into mature miRNAs(14). Dicer, a member of the RNase III superfamily of bidentate nucleases, mediates the latter step(15-19), whereas the processing enzyme for the former step is unknown. Here we identify another RNase III, human Drosha, as the core nuclease that executes the initiation step of miRNA processing in the nucleus. Immunopurified Drosha cleaved pri-miRNA to release pre-miRNA in vitro. Furthermore, RNA interference of Drosha resulted in the strong accumulation of pri-miRNA and the reduction of pre-miRNA and mature miRNA in vivo. Thus, the two RNase III proteins, Drosha and Dicer, may collaborate in the stepwise processing of miRNAs, and have key roles in miRNA-mediated gene regulation in processes such as development and differentiation.

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