Somatic Primary piRNA Biogenesis Driven by cis-Acting RNA Elements and trans-Acting Yb
Somatic Primary piRNA Biogenesis Driven by cis-Acting RNA Elements and trans-Acting Yb
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DOI：
10.1016/j.celrep.2015.06.035
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发表时间：
2015-07-21
期刊：
影响因子：
8.8
通讯作者：
Siomi, Mikiko C.
中科院分区：
文献类型：
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作者：
Ishizu, Hirotsugu;Iwasaki, Yuka W.;Siomi, Mikiko C.
果蝇卵巢体细胞中的初级piRNA来自皮尔纳簇转录物和mRNA子集的30个UTR，包括Traffic jam（Tj）mRNA。然而，尚不清楚这些RNA如何被确定为主要皮尔纳来源。在这里，我们鉴定了Tj 3' UTR中的顺式作用100-nt片段，其足以从未整合的DNA产生人工piRNA。这些人工piRNA在内源基因转录沉默中是有效的。Yb是初级皮尔纳生物发生中心Yb体的核心组分，直接结合Tj-cis元件。这种相互作用的破坏显著降低了皮尔纳的产生。因此，Yb是Tj-cis元件的反式作用伙伴。Yb-CLIP揭示Yb结合与体细胞皮尔纳产生相关，但Tj-cis元件下游序列产生很少的人工piRNA。因此，我们提出Yb通过两种作用模式确定初级皮尔纳来源：初级结合到顺式元件以指定底物，次级结合到下游区域以增加皮尔纳群体的多样性。
Primary piRNAs in Drosophila ovarian somatic cells arise from piRNA cluster transcripts and the 30 UTRs of a subset of mRNAs, including Traffic jam (Tj) mRNA. However, it is unclear how these RNAs are determined as primary piRNA sources. Here, we identify a cis-acting 100-nt fragment in the Tj 3' UTR that is sufficient for producing artificial piRNAs from unintegrated DNA. These artificial piRNAs were effective in endogenous gene transcriptional silencing. Yb, a core component of primary piRNA biogenesis center Yb bodies, directly bound the Tj-cis element. Disruption of this interaction markedly reduced piRNA production. Thus, Yb is the transacting partner of the Tj-cis element. Yb-CLIP revealed that Yb binding correlated with somatic piRNA production but Tj-cis element downstream sequences produced few artificial piRNAs. We thus propose that Yb determines primary piRNA sources through two modes of action: primary binding to cis elements to specify substrates and secondary binding to downstream regions to increase diversity in piRNA populations.