National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.
University of the Chinese Academy of Sciences, Beijing 100049, China.
Plant Cell. 2021 Jul 19;33(6):1980-1996. doi: 10.1093/plcell/koab090.
MicroRNAs (miRNAs) control various biological processes by repressing target mRNAs. In plants, miRNAs mediate target gene repression via both mRNA cleavage and translational repression. However, the mechanism underlying this translational repression is poorly understood. Here, we found that Arabidopsis thaliana HYPONASTIC LEAVES1 (HYL1), a core component of the miRNA processing machinery, regulates miRNA-mediated mRNA translation but not miRNA biogenesis when it localized in the cytoplasm. Cytoplasmic HYL1 localizes to the endoplasmic reticulum and associates with ARGONAUTE1 (AGO1) and ALTERED MERISTEM PROGRAM1. In the cytoplasm, HYL1 monitors the distribution of AGO1 onto polysomes, binds to the mRNAs of target genes, represses their translation, and partially rescues the phenotype of the hyl1 null mutant. This study uncovered another function of HYL1 and provides insight into the mechanism of plant gene regulation.
microRNAs (miRNAs) 通过抑制靶 mRNAs 来控制各种生物过程。在植物中，miRNAs 通过 mRNA 切割和翻译抑制来介导靶基因的抑制。然而，这种翻译抑制的机制还知之甚少。在这里，我们发现拟南芥 HYPONASTIC LEAVES1 (HYL1)，一种 miRNA 加工机制的核心组成部分，当它定位于细胞质中时，调节 miRNA 介导的 mRNA 翻译，但不调节 miRNA 的生物发生。细胞质中的 HYL1 定位于内质网，并与 ARGONAUTE1 (AGO1) 和 ALTERED MERISTEM PROGRAM1 相关联。在细胞质中，HYL1 监测 AGO1 在上核糖体的分布，与靶基因的 mRNAs 结合，抑制它们的翻译，并部分挽救 hyl1 缺失突变体的表型。本研究揭示了 HYL1 的另一个功能，并为植物基因调控的机制提供了新的见解。
