Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA, USA.
Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China.
Nat Plants. 2020 Aug;6(8):957-969. doi: 10.1038/s41477-020-0726-z. Epub 2020 Jul 20.
Unlike in metazoans, the stepwise biogenesis of microRNAs (miRNAs) in plants occurs within the nucleus. Whether or how the major steps in miRNA biogenesis are coordinated is largely unknown. Here we show that the plant TREX-2 complex promotes multiple steps in miRNA biogenesis, including transcription, processing and nuclear export. THP1 and SAC3A-the core subunits of TREX-2-interact and colocalize with RNA polymerase II to promote the transcription of MIR genes in the nucleoplasm. TREX-2 interacts with the microprocessor component SERRATE and promotes the formation of dicing bodies in the nucleoplasm. THP1 also interacts and colocalizes with the nucleoporin protein NUP1 at the nuclear envelope. NUP1 and THP1 promote the nuclear export of miRNAs and ARGONAUTE1. These results suggest that TREX-2 coordinates the transcription, processing and export steps in miRNA biogenesis to ensure efficient miRNA production.
与后生动物不同，植物 microRNAs (miRNAs) 的逐步生物发生发生在细胞核内。miRNA 生物发生的主要步骤是否以及如何协调在很大程度上尚不清楚。在这里，我们表明植物 TREX-2 复合物促进 miRNA 生物发生的多个步骤，包括转录、加工和核输出。THP1 和 SAC3A——TREX-2 的核心亚基——相互作用并与 RNA 聚合酶 II 共定位，以促进核质中 MIR 基因的转录。TREX-2 与微处理器成分 SERRATE 相互作用，并促进核质中切割体的形成。THP1 还与核孔蛋白 NUP1 在核膜上相互作用和共定位。NUP1 和 THP1 促进 miRNA 和 ARGONAUTE1 的核输出。这些结果表明，TREX-2 协调 miRNA 生物发生的转录、加工和输出步骤，以确保有效的 miRNA 产生。
