转座子是一类可以在染色体上或不同染色体间自由移动的DNA。在高等生物中,处于活跃状态的转座子多为通过RNA中间体进行转座的逆转录转座子。由于逆转录转座子在细胞基因组中占有很高的比例,它的频繁转座能引起细胞基因组结构和功能的改变,导致癌症等严重基因疾病的发生,因此宿主细胞在长期的进化中形成了多种自我保护机制用以控制逆转录转座子活性。属于非编码小RNA的piRNA以其独特的机制在转录及转录后水平控制逆转录转座子RNA中间体的产生,抑制了逆转录转座过程的发生。本文总结了近年来piRNA控制转座子转座相关分子机制的研究进展,以期为转座子及基因调控方面的研究工作提供一些参考。

Transposable elements (TEs) are DNA elements that can change their position within or between chromosomes. Most active TEs are retrotransposons, which transpose through a RNA intermediate. Since retrotransposons comprise high proportions in cell genomes, their frequent transposition may cause deleterious effects on the structure and function of the host cell genomes, thus causing serious genetic diseases such as cancer. Host cells therefore developed defense strategies to restrict these mobile elements. piRNA, which belongs to non-coding interfering RNAs, can efficiently decrease the level of retrotransposon RNA intermediates at transcriptional or post-transcriptional stages. In this review, we summarize the progress in mechanisms of piRNA-mediated retrotransposon inhibition. We hope that this review may shed light on the research of transposon and genome regulation.