microRNAs(miRNAs)是小的非编码内源性RNA分子,18-24个核苷酸长,在真核生物中通过转录后基因沉默控制多个基因调控途径。为了全面了解陆地植物中miRNA生物发生和作用的进化史,需要对苔藓植物代表进行研究。这里,我们回顾了目前对紫草MIR基因结构的理解,miRNA生物发生,和功能,专注于简单的类针叶菊和复杂的类针叶菊。我们回顾了关于保守和非保守miRNA的已知信息,他们的目标,以及miRNA在多形性分枝杆菌和单纯性分枝杆菌中的作用的功能意义。我们注意到大多数多态M.morphamiRNA在蛋白质编码基因中编码,并提供了被识别为独立转录单位的23个MIR基因结构的数据。我们鉴定了与高等植物中鉴定的那些同源的参与miRNA生物发生的多态分枝杆菌基因,包括那些编码核心微处理器组件和其他影响稳定性的辅助和调节蛋白,折叠,和pri-miRNA的加工。我们分析了miRNA生物发生蛋白,并在大多数情况下发现了相似的结构域结构。我们的数据支持这样的假设,即高等植物中几乎所有的miRNA生物发生因子也存在于苔藓中,表明它们在陆地植物进化的早期出现。
MicroRNAs (miRNAs) are small non-coding endogenous RNA molecules, 18-24 nucleotides long, that control multiple gene regulatory pathways via post-transcriptional gene silencing in eukaryotes. To develop a comprehensive picture of the evolutionary history of miRNA biogenesis and action in land plants, studies on bryophyte representatives are needed. Here, we review current understanding of liverwort MIR gene structure, miRNA biogenesis, and function, focusing on the simple thalloid Pellia endiviifolia and the complex thalloid Marchantia polymorpha. We review what is known about conserved and non-conserved miRNAs, their targets, and the functional implications of miRNA action in M. polymorpha and P. endiviifolia. We note that most M. polymorpha miRNAs are encoded within protein-coding genes and provide data for 23 MIR gene structures recognized as independent transcriptional units. We identify M. polymorpha genes involved in miRNA biogenesis that are homologous to those identified in higher plants, including those encoding core
microprocessor components and other auxiliary and regulatory proteins that influence the stability, folding, and processing of pri-miRNAs. We analyzed miRNA biogenesis proteins and found similar domain architecture in most cases. Our data support the hypothesis that almost all miRNA biogenesis factors in higher plants are also present in liverworts, suggesting that they emerged early during land plant evolution.