26G endo-siRNAs regulate spermatogenic and zygotic gene expression in Caenorhabditis elegans
26G endo-siRNAs regulate spermatogenic and zygotic gene expression in Caenorhabditis elegans
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DOI：
10.1073/pnas.0906378106
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发表时间：
2009-11-03
影响因子：
11.1
通讯作者：
Kim, John K.
中科院分区：
文献类型：
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作者：
Han, Ting;Manoharan, Arun Prasad;Kim, John K.
内源性小干扰RNA（endo-siRNA）通过结合和切割mRNA靶标或介导异染色质形成来调节真核生物中的多种基因表达程序;然而，endo-siRNA生物合成、分选和靶标调节的机制仍然知之甚少。在这里，我们报告了秀丽隐杆线虫中一类特定的种系产生的endo-siRNA的鉴定和功能，这些endo-siRNA长26 nt，在第一个核苷酸位置含有鸟嘌呤（即，26G RNA）。26 G RNA在精子发生和合子发育过程中调节基因表达，它们的生物发生需要ERI-1外切核酸酶和RRF-3 RNA依赖性RNA聚合酶（RdRP）。值得注意的是，我们确定了26 G RNA的两个不重叠的亚类，它们分为特定的RNA诱导沉默复合物（RISC），并差异调节不同的mRNA靶点。I类26 G RNA靶基因在精子发生过程中表达，而II类26 G RNA是母系遗传的，在合子发育过程中沉默基因表达。这些发现暗示了一类endo-siRNA在生育和发育所需的转录程序的全局调节中。
Endogenous small interfering RNAs (endo-siRNAs) regulate diverse gene expression programs in eukaryotes by either binding and cleaving mRNA targets or mediating heterochromatin formation; however, the mechanisms of endo-siRNA biogenesis, sorting, and target regulation remain poorly understood. Here we report the identification and function of a specific class of germline-generated endo-siRNAs in Caenorhabditis elegans that are 26 nt in length and contain a guanine at the first nucleotide position (i.e., 26G RNAs). 26G RNAs regulate gene expression during spermatogenesis and zygotic development, and their biogenesis requires the ERI-1 exonuclease and the RRF-3 RNA-dependent RNA polymerase (RdRP). Remarkably, we identified two nonoverlapping subclasses of 26G RNAs that sort into specific RNA-induced silencing complexes (RISCs) and differentially regulate distinct mRNA targets. Class I 26G RNAs target genes are expressed during spermatogenesis, whereas class II 26G RNAs are maternally inherited and silence gene expression during zygotic development. These findings implicate a class of endo-siRNAs in the global regulation of transcriptional programs required for fertility and development.