Yao Chengguo, Zhao Botao, Li Wei, Li Yang, Qin Wenming, Huang Bing, Jin Youxin
State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences; Graduate School of Chinese Academy of Sciences, Shanghai 200031, China.
Acta Biochim Biophys Sin (Shanghai). 2007 Nov;39(11):829-34. doi: 10.1111/j.1745-7270.2007.00346.x.
Plant small non-coding RNAs including microRNAs (miRNAs), small interfering RNAs (siRNAs) and trans-acting siRNAs, play important roles in modulating gene expression in cells. Here we isolated 21 novel endogenous small RNA molecules, ranging from 18 to 24 nucleotides, in Oryza sativa that can be mapped to 111 hairpin precursors. Further analysis indicated that most of these hairpin sequences originated from putative miniature inverted-repeat transposable elements, a major type of DNA transposon. Considering that miRNA is characteristic of hairpin-like precursor and plant endogenous siRNAs are often located at transposon regions, we hypothesized that our cloned small RNAs might represent the intermediate product in the evolutionary process between siRNAs and miRNAs. Northern blot analysis indicated that five of them were much more abundantly expressed in flower compared to other tissues, implying their potential function in inflorescence. In conclusion, our results enrich rice small RNA data and provide a meaningful perspective for small RNA annotation in plants.
植物中的小非编码RNA，包括微小RNA（miRNA）、小干扰RNA（siRNA）和反式作用siRNA，在调节细胞基因表达中发挥着重要作用。在此，我们在水稻中分离出了21种新的内源性小RNA分子，长度在18至24个核苷酸之间，这些分子可定位到111个发夹前体上。进一步分析表明，这些发夹序列大多源自假定的微型反向重复转座元件，这是DNA转座子的一种主要类型。鉴于miRNA具有发夹样前体的特征，且植物内源性siRNA常位于转座子区域，我们推测我们克隆的小RNA可能代表了siRNA和miRNA进化过程中的中间产物。Northern印迹分析表明，其中5种在花中的表达量远高于其他组织，这暗示了它们在花序中的潜在功能。总之，我们的结果丰富了水稻小RNA数据，并为植物小RNA注释提供了有意义的视角。
