Institute of Molecular and Cellular Biosciences, Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
EMBO Rep. 2013 Jul;14(7):652-8. doi: 10.1038/embor.2013.73. Epub 2013 Jun 4.
Plant ARGONAUTE7 (AGO7) assembles RNA-induced silencing complex (RISC) specifically with miR390 and regulates the auxin-signalling pathway via production of TAS3 trans-acting siRNAs (tasiRNAs). However, how AGO7 discerns miR390 among other miRNAs remains unclear. Here, we show that the 5' adenosine of miR390 and the central region of miR390/miR390* duplex are critical for the specific interaction with AGO7. Furthermore, despite the existence of mismatches in the seed and central regions of the duplex, cleavage of the miR390* strand is required for maturation of AGO7-RISC. These findings suggest that AGO7 uses multiple checkpoints to select miR390, thereby circumventing promiscuous tasiRNA production.
植物 ARGONAUTE7（AGO7）特异性地与 miR390 组装 RNA 诱导沉默复合物（RISC），并通过产生 TAS3 反式作用 siRNA（tasiRNA）来调节生长素信号通路。然而，AGO7 如何在其他 miRNA 中识别 miR390 仍然不清楚。在这里，我们表明 miR390 的 5' 腺苷和 miR390/miR390双链体的中心区域对于与 AGO7 的特异性相互作用至关重要。此外，尽管双链体的种子和中心区域存在错配，但 miR390链的切割对于 AGO7-RISC 的成熟是必需的。这些发现表明 AGO7 使用多个检查点来选择 miR390，从而避免产生混杂的 tasiRNA。
