Li Mu, Yu Bin
School of Biological Sciences & Center for Plant Science Innovation University of Nebraska-Lincoln, Lincoln, Nebraska USA.
RNA Biol. 2021 Dec;18(12):2087-2096. doi: 10.1080/15476286.2021.1899491. Epub 2021 Mar 17.
MicroRNAs (miRNAs) are essential non-coding riboregulators of gene expression in plants and animals. In plants, miRNAs guide their effector protein named ARGONAUTE (AGO) to find target RNAs for gene silencing through target RNA cleavage or translational inhibition. miRNAs are derived from primary miRNA transcripts (pri-miRNAs), most of which are transcribed by the DNA-dependent RNA polymerase II. In plants, an RNase III enzyme DICER-LIKE1-containing complex processes pri-miRNAs in the nucleus into miRNAs. To ensure proper function of miRNAs, plants use multiple mechanisms to control miRNA accumulation. On one hand, pri-miRNA levels are controlled through transcription and stability. On the other hand, the activities of the DCL1 complex are regulated by many protein factors at transcriptional, post-transcriptional and post-translational levels. Notably, recent studies reveal that pri-miRNA structure/sequence features and modifications also play important roles in miRNA biogenesis. In this review, we summarize recent progresses on the mechanisms regulating miRNA biogenesis.
微小RNA（miRNA）是植物和动物中基因表达必不可少的非编码核糖调节因子。在植物中，miRNA引导其效应蛋白AGO（AGO）通过靶RNA切割或翻译抑制来寻找靶RNA以进行基因沉默。miRNA来源于初级miRNA转录本（pri-miRNA），其中大部分由DNA依赖性RNA聚合酶II转录。在植物中，含核糖核酸酶III的DICER-LIKE1复合物在细胞核中将pri-miRNA加工成miRNA。为确保miRNA的正常功能，植物使用多种机制来控制miRNA的积累。一方面，pri-miRNA水平通过转录和稳定性来控制。另一方面，DCL1复合物的活性在转录、转录后和翻译后水平受到许多蛋白质因子的调节。值得注意的是，最近的研究表明，pri-miRNA的结构/序列特征和修饰在miRNA生物合成中也起着重要作用。在这篇综述中，我们总结了miRNA生物合成调控机制的最新进展。
