Endogenous RNA interference provides a somatic Defense against Drosophila transposons
Endogenous RNA interference provides a somatic Defense against Drosophila transposons
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DOI：
10.1016/j.cub.2008.05.006
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发表时间：
2008-06-03
期刊：
影响因子：
9.2
通讯作者：
Lai, Eric C.
中科院分区：
文献类型：
--
作者：
Chung, Wei-Jen;Okamura, Katsutomo;Lai, Eric C.
背景：由于移动的遗传元件的致突变后果，已经进化出复杂的防御来限制它们的活性。在果蝇和脊椎动物中控制转座因子（TE）活性的主要系统由Piwi相互作用RNA（piRNA）介导，其类似于由Piwi类效应子结合的24-30个核苷酸的RNA。皮尔纳系统被认为主要提供对TE activity.Results的生殖系防御：在这里，我们描述了第二个系统，通过使用内源性小干扰RNA（siRNA），这是21个核苷酸，3 '端修饰的RNA依赖于Dicer-2和Argonaute-2抑制果蝇TE。与piRNA相反，我们发现TE-siRNA系统在体细胞组织中是有活性的，特别是在各种永生化细胞系中。TE衍生的小RNA的模式和性质的分析揭示了TE区域和分别转化为piRNA和siRNA的基因组基因座之间的进一步区别。最后，功能测试表明，Dicer-2或Argonaute-2缺陷的细胞和动物组织中，许多转座子转录物积累到更高的水平。结论：果蝇利用两种小RNA系统来限制转座子在生殖细胞（主要通过piRNA）和索马（主要通过siRNA）中的活性。
Background: Because of the mutagenic consequences of mobile genetic elements, elaborate defenses have evolved to restrict their activity. A major system that controls the activity of transposable elements (TEs) in flies and vertebrates is mediated by Piwi-interacting RNAs (piRNAs), which are similar to 24-30 nucleotide RNAs that are bound by Piwi-class effectors. The piRNA system is thought to provide primarily a germline defense against TE activity.Results: Here, we describe a second system that represses Drosophila TEs by using endogenous small interfering RNAs (siRNAs), which are 21 nucleotide, 3'-end-modified RNAs that are dependent on Dicer-2 and Argonaute-2. In contrast to piRNAs, we find that the TE-siRNA system is active in somatic tissues, and particularly so in various immortalized cell lines. Analysis of the patterns and properties of TE-derived small RNAs reveals further distinctions between TE regions and genomic loci that are converted into piRNAs and siRNAs, respectively. Finally, functional tests show that many transposon transcripts accumulate to higher levels in cells and animal tissues that are deficient for Dicer-2 or Argonaute-2.Conclusions: Drosophila utilizes two small-RNA systems to restrict transposon activity in the germline (mostly via piRNAs) and in the soma (mostly via siRNAs).