piRNA的生物学功能

Biological Funtions of piRNA

非编码小RNA(non-codingRNA,ncRNA)主要有siRNA(smallinterferingRNA)、miRNA(microRNA)和piRNA(piwi-interactingRNA)三类,其中piRNA是近年来新发现的一类小RNA分子,特异性地同Argonuat蛋白家族中的Piwi亚家族蛋白结合,主要在生殖细胞系中表达,对维持生殖系DNA完整、抑制转座子转录、抑制翻译、参与异染色质的形成、执行表观遗传调控和生殖细胞发生等均有重要作用.piRNA基因几乎遍布于整个基因组,但呈高度不连续性分布,大部分定位于20～90kb的染色体基因簇上.与来自于双链RNA的siRNA和发卡结构miRNA不同之处是piRNA来自长单链RNA前体,或者是两股非重叠的反向转录前体,其生成与Dicer无关.作为调节RNA(riboregulator),piRNA和miRNA可能在动物起源早期就已经出现了,帮助生命进入了一个多细胞动物的时代,产生了今天的生物体复杂性和多样性.piRNA成为ncRNA的研究热点,进展飞快,有很多综述及时介绍piRNA的研究进展,本文结合siRNA、miRNA的特点介绍了关于piRNA的形成机制和作用的最新研究成果.

The non-coding RNAs（ncRNAs） has three major families,siRNA（small interfering RNA）,miRNA（microRNA） and piRNA（piwi-interacting RNA）.The piRNAs bind specifically to the piwi proteins of the Argonaute familys,and functioned in the maintainance of germline DNA integrity,silencing of transposon transcription,translation suppression,heterochromatin formation,epigenetic regulation and gametogenesis.The piRNA-coding sequences are often located discontinuously throughout the genome in clusters of 20～90 kb. Different from the siRNAs or miRNAs, which are derived from double-stranded or short-hairpin RNA precursors, piRNAs are derived from single-stranded RNA precursors or two non-overlapping and divergently transcribed precursors without the involvement of Dicer endonucleases. As a class of small riboregulators, piRNA was originated since the dawn of animal evolution. It might have promoted the formation of multi cellular animal species and contributed to the current complexities and diversities of life forms. This review intends to introduce the latest results related to the mechanisms of formation and functions of oiRNAs.