Yang Li, Liu Ziqiang, Lu Feng, Dong Aiwu, Huang Hai
National Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
Plant J. 2006 Sep;47(6):841-50. doi: 10.1111/j.1365-313X.2006.02835.x. Epub 2006 Aug 2.
The Arabidopsis gene SERRATE (SE) controls leaf development, meristem activity, inflorescence architecture and developmental phase transition. It has been suggested that SE, which encodes a C(2)H(2) zinc finger protein, may change gene expression via chromatin modification. Recently, SE has also been shown to regulate specific microRNAs (miRNAs), miR165/166, and thus control shoot meristem function and leaf polarity. However, it remains unclear whether and how SE modulates specific miRNA processing. Here we show that the se mutant exhibits some similar developmental abnormalities as the hyponastic leaves1 (hyl1) mutant. Since HYL1 is a nuclear double-stranded RNA-binding protein acting in the DICER-LIKE1 (DCL1) complex to regulate the first step of primary miRNA transcript (pri-miRNA) processing, we hypothesized that SE could play a previously unrecognized and general role in miRNA processing. Genetic analysis supports that SE and HYL1 act in the same pathway to regulate plant development. Consistently, SE is critical for the accumulation of multiple miRNAs and the trans-acting small interfering RNA (ta-siRNA), but is not required for sense post-transcriptional gene silencing. We further demonstrate that SE is localized in the nucleus and interacts physically with HYL1. Finally, we provide evidence that SE and HYL1 probably act with DCL1 in processing pri-miRNAs before HEN1 in miRNA biogenesis. In plants and animals, miRNAs are known to be processed in a stepwise manner from pri-miRNA. Our data strongly suggest that SE plays an important and general role in pri-miRNA processing, and it would be interesting to determine whether animal SE homologues may play similar roles in vivo.
拟南芥基因锯齿状（SE）控制叶片发育、分生组织活性、花序结构和发育阶段转变。有人提出，编码C(2)H(2)锌指蛋白的SE可能通过染色质修饰改变基因表达。最近，SE还被证明可调节特定的微小RNA（miRNA），即miR165/166，从而控制茎尖分生组织功能和叶片极性。然而，SE是否以及如何调节特定miRNA的加工仍不清楚。在这里，我们表明se突变体表现出与下弯叶1（hyl1）突变体一些相似的发育异常。由于HYL1是一种核双链RNA结合蛋白，在Dicer样1（DCL1）复合物中发挥作用，调节初级miRNA转录本（pri-miRNA）加工的第一步，我们推测SE可能在miRNA加工中发挥了以前未被认识到的普遍作用。遗传分析支持SE和HYL1在同一途径中调节植物发育。一致的是，SE对多种miRNA和反式作用小干扰RNA（ta-siRNA）的积累至关重要，但对有义转录后基因沉默不是必需的。我们进一步证明SE定位于细胞核中，并与HYL1发生物理相互作用。最后，我们提供证据表明，在miRNA生物合成中，SE和HYL1可能在HEN1之前与DCL1一起加工pri-miRNA。在植物和动物中，已知miRNA是从pri-miRNA逐步加工而来的。我们的数据强烈表明，SE在pri-miRNA加工中发挥重要且普遍的作用，确定动物SE同源物在体内是否可能发挥类似作用将是很有趣的。
