Dicing of viral replication intermediates during silencing of latent Drosophila viruses
Dicing of viral replication intermediates during silencing of latent Drosophila viruses
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DOI：
10.1073/pnas.0813412106
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发表时间：
2009-03-31
影响因子：
11.1
通讯作者：
Lai, Eric C.
中科院分区：
文献类型：
--
作者：
Flynt, Alex;Liu, Na;Lai, Eric C.
先前的研究揭示了RNA干扰（RNAi）在植物、线虫和苍蝇对病毒感染的即时细胞反应中的作用。然而，对于RNAi如何在持续或潜伏感染期间对抗病毒，我们知之甚少。我们对从潜伏感染禽舍病毒（FHV）的果蝇细胞中克隆的小rna的分析未能揭示病毒基因组大量降解的特征。相反，这种+链病毒特异性地产生dicer -2依赖性的21核苷酸sirna，这些sirna以相同的比例从+链和-链中衍生出来。奇怪的是，与丰富的病毒sinas完全互补的荧光素酶报告蛋白很少受到抑制。此外，尽管病毒sirna被整合到与Argonaute2相关的效应复合体中，但潜伏感染细胞中的大量FHV sirna并未被装载到任何Argonaute蛋白中。总之，这些数据表明，直接切割病毒复制中间体在维持潜伏病毒状态中起着重要作用。此外，效应复合物对大量病毒sirna的拒绝表明，RNA双链结构能力之外的标准影响了功能性沉默复合物的组装。
Previous studies revealed roles for RNA interference (RNAi) in the immediate cellular response to viral infection in plants, nematodes and flies. However, little is known about how RNAi combats viruses during persistent or latent infections. Our analysis of small RNAs cloned from Drosophila cells latently infected with Flock House Virus (FHV) failed to reveal signatures of bulk degradation of the viral genome. Instead, this + strand virus specifically generated Dicer-2-dependent, 21-nucleotide siRNAs that derived in equal proportion from + and - strands. Curiously, luciferase reporters that are fully complementary to abundant viral siRNAs were poorly repressed. Moreover, although the viral siRNAs that were incorporated into an effector complex associated with Argonaute2, bulk FHV siRNAs in latently infected cells were not loaded into any Argonaute protein. Together, these data suggest that direct dicing of viral replication intermediates plays an important role in maintaining the latent viral state. In addition, the denial of bulk viral siRNAs from effector complexes suggests that criteria beyond the structural competency of RNA duplexes influence the assembly of functional silencing complexes.