Millar Anthony A, Lohe Allan, Wong Gigi
Division of Plant Science, Research School of Biology, The Australian National University, Canberra ACT 2601, Australia.
Plants (Basel). 2019 Jul 30;8(8):255. doi: 10.3390/plants8080255.
MicroR159 (miR159) is ancient, being present in the majority of land plants where it targets a class of regulatory genes called or via highly conserved miR159-binding sites. These genes encode R2R3 MYB domain transcription factors that transduce the gibberellin (GA) signal in the seed aleurone and the anther tapetum. Here, plays a conserved role in promoting the programmed cell death of these tissues, where miR159 function appears weak. By contrast, is not involved in GA-signaling in vegetative tissues, but rather its expression is deleterious, leading to the inhibition of growth and development. Here, the major function of miR159 is to mediate strong silencing of to enable normal growth. Highlighting this requirement of strong silencing are conserved RNA secondary structures associated with the miR159-binding site in mRNA that promotes miR159-mediated repression. Although the miR159- pathway in vegetative tissues has been implicated in a number of different functions, presently no conserved role for this pathway has emerged. We will review the current knowledge of the different proposed functions of miR159, and how this ancient pathway has been used as a model to help form our understanding of miRNA biology in plants.
微小RNA159（miR159）存在已久，在大多数陆地植物中都有，它通过高度保守的miR159结合位点靶向一类称为 或 的调控基因。这些 基因编码R2R3 MYB结构域转录因子，它们在种子糊粉层和花药绒毡层中传导赤霉素（GA）信号。在这里， 在促进这些组织的程序性细胞死亡中发挥保守作用，而miR159在这些组织中的功能似乎较弱。相比之下， 在营养组织中不参与GA信号传导，但其表达是有害的，会导致生长和发育受到抑制。在这里，miR159的主要功能是介导对 的强沉默，以实现正常生长。与 信使核糖核酸（mRNA）中的miR159结合位点相关的保守RNA二级结构突出了这种强沉默的必要性，该结构促进了miR159介导的抑制作用。尽管营养组织中的miR159 - 途径涉及许多不同功能，但目前该途径尚未出现保守作用。我们将回顾目前关于miR159不同功能的现有知识，以及这条古老途径如何被用作模型来帮助我们理解植物中的微小RNA生物学。
