The diversity of post-transcriptional gene silencing mediated by small silencing RNAs in plants.
The diversity of post-transcriptional gene silencing mediated by small silencing RNAs in plants.
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DOI：
10.1042/ebc20200006
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发表时间：
2020-09
影响因子：
6.4
通讯作者：
Huijuan Tan;Bosheng Li;Hongwei Guo
中科院分区：
文献类型：
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作者：
Huijuan Tan;Bosheng Li;Hongwei Guo
在植物中，转录后基因沉默(PTGS)严格调控发育，维持基因组稳定，保护植物免受外源基因的侵袭。PTGS可由病毒感染、转基因和内源性转录物触发，因此通常作为一种基于RNA的免疫机制。相应地，根据启动因素的不同，PTGS可分为病毒PTGS、转基因PTGS和内源基因PTGS。与频繁经历PTGS的高表达入侵转基因和病毒基因不同，大多数内源基因不会触发PTGS，除了少数能产生内源小RNA(SRNAs)的基因，包括microRNA(MiRNA)和小干扰RNA(SiRNA)。不同长度的miRNA和siRNA，主要是21、22或24个核苷酸(NT)，发挥着不同的功能，从靶mRNA降解、翻译抑制、DNA甲基化和染色质修饰。大量的21-NT miRNA或siRNA分别由RNase-III酶Dector-like 1(DCL1)和DCL4处理，在PTGS途径中得到了很好的研究。相比之下，主要由DCL2处理的内源性22-NT sRNA的稀缺限制了他们的研究，尽管最近有一些令人鼓舞的研究报道。因此，我们回顾了目前对由多种sRNA触发的不同PTGS通路的理解，并总结了22-ntsRNA介导的PTGS的不同特征。
In plants, post-transcriptional gene silencing (PTGS) tightly regulates development, maintains genome stability and protects plant against foreign genes. PTGS can be triggered by virus infection, transgene, and endogenous transcript, thus commonly serves as an RNA-based immune mechanism. Accordingly, based on the initiating factors, PTGS can be divided into viral-PTGS, transgene-PTGS, and endo-gene-PTGS. Unlike the intensely expressed invading transgenes and viral genes that frequently undergo PTGS, most endogenous genes do not trigger PTGS, except for a few that can produce endogenous small RNAs (sRNAs), including microRNA (miRNA) and small interfering RNA (siRNA). Different lengths of miRNA and siRNA, mainly 21-, 22- or 24-nucleotides (nt) exert diverse functions, ranging from target mRNA degradation, translational inhibition, or DNA methylation and chromatin modifications. The abundant 21-nt miRNA or siRNA, processed by RNase-III enzyme DICER-LIKE 1 (DCL1) and DCL4, respectively, have been well studied in the PTGS pathways. By contrast, the scarceness of endogenous 22-nt sRNAs that are primarily processed by DCL2 limits their research, although a few encouraging studies have been reported recently. Therefore, we review here our current understanding of diverse PTGS pathways triggered by a variety of sRNAs and summarize the distinct features of the 22-nt sRNA mediated PTGS.