Ramachandran Vanitharani, Chen Xuemei
Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA 92521, USA.
Trends Plant Sci. 2008 Jul;13(7):368-74. doi: 10.1016/j.tplants.2008.03.008. Epub 2008 May 22.
The Arabidopsis genome encodes two major classes of 20-24-nucleotide riboregulators: microRNAs and small interfering RNAs. These small RNAs act as sequence-specific repressors of target gene expression, either at the transcriptional level through DNA and/or histone methylation or at the post-transcriptional level through transcript cleavage or translational inhibition. Small RNAs are processed from precursor RNAs by one or more of the four DICER-LIKE RNase III enzymes, modified by HUA ENHANCER 1, a small RNA methyltransferase, and loaded onto an argonaute protein-containing RNA-induced silencing complex. Here, we review the biogenesis of small RNAs, and we discuss the major outstanding questions in small RNA metabolism and function.
拟南芥基因组编码两大类20 - 24个核苷酸的核糖调节因子：微小RNA和小干扰RNA。这些小RNA作为靶基因表达的序列特异性抑制因子，在转录水平通过DNA和/或组蛋白甲基化发挥作用，或在转录后水平通过转录本切割或翻译抑制发挥作用。小RNA由四种类似Dicer的核糖核酸酶III中的一种或多种从前体RNA加工而来，由小RNA甲基转移酶HUA增强子1修饰，并装载到含AGO蛋白的RNA诱导沉默复合体上。在此，我们综述小RNA的生物合成，并讨论小RNA代谢和功能方面的主要悬而未决的问题。
