《生命科学》 2018, 30(8): 831-839

植物中phasiRNA研究进展

朱成新， 熊　伟， 莫蓓莘*

(深圳大学生命与海洋科学学院植物表观遗传实验室，深圳 518060)

摘　要：摘　要：植物phasiRNA (phased， secondary， small interfering RNA) 是一类内源性的、起调控作用的非编码小RNA (sRNA)，它在植物的生长、发育、生殖以及抗病中发挥着重要作用。PhasiRNA 初级转录本由Pol II(RNA polymerase II) 转录，随后miRNA (microRNA) 引导AGO 蛋白对phasiRNA 初级转录本上的靶位点进行剪切，剪切后的phasiRNA 前体片段( 剪切位点的上游或下游片段) 继而被RDR6 (RNA-dependent RNA polymerases 6) 复制成双链RNA，双链RNA 被DCL4 切割成一系列首尾相接，具有一定相位的21-nt 或24-nt的小RNA，即phasiRNA。成熟的phasiRNA 与AGO 蛋白组装成沉默复合体，作用于靶基因，发挥转录后调控的功能。该文对植物phasiRNA 的生物合成通路、生物学功能及其进化进行综述。

Recent studies on phasiRNAs in plants

ZHU Cheng-Xin， XIONG Wei， MO Bei-Xin*

(Plant Epigenetic Laboratory， College of Life Sciences and Oceanography， Shenzhen University， Shenzhen 518060， China)

Abstract: Abstract: Plant phasiRNAs (phased， secondary， small interfering RNAs) play important roles in plant growth， development， reproduction as well as resistance to virus. The primary phasiRNAs (pri-phasiRNAs) are transcripted
    by Pol II (DNA dependant RNA polymerase II). Then， pri-phasiRNAs are cleaved by AGO protein， which is guided by miRNA， to form the precursor phasiRNAs (pre-phasiRNAs). One portion of single-strand RNA (upstream or downstream of the miRNA cleavage site) will be converted by RDR6 (RNA-dependent RNA polymerases 6) into double-strand RNA， which is then cut by DCL4 into 21-nt or 24-nt phased mature phasiRNAs. Mature phasiRNA assembles with AGO protein into silencing complex to influence target gene expression at the posttranscriptional level. This paper will review the biosynthesis pathway， biological function and evolution of phasiRNA in plants.