siRNA in human cells selectively localizes to target RNA sites
siRNA in human cells selectively localizes to target RNA sites
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DOI：
10.1073/pnas.0600148103
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发表时间：
2006-05-16
影响因子：
11.1
通讯作者：
Deniz, Ashok A.
中科院分区：
文献类型：
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作者：
Berezhna, Svitlana Y.;Supekova, Lubica;Deniz, Ashok A.
最近在人类细胞核中对RNA干扰（RNAi）的观察提出了关于细胞核和细胞质RNAi途径共享程度的关键问题。通过直接可视化小干扰RNA（siRNA）在活的人类细胞中的定位，我们在这里显示siRNA选择性地定位在细胞质中或易位到细胞核中，这取决于沉默靶RNA驻留的位置。靶向小核7SK和U6 RNA的两种siRNA以双链体定位于核中。相反，靶向细胞质丙型肝炎病毒复制子RNA的siRNA解离，并且仅反义链分布在携带靶RNA的细胞的细胞质中，而有义链被降解。同时，后者siRNA的两条链分布在缺乏沉默靶RNA的细胞中的整个细胞质和细胞核中。这些结果表明存在一种机制，通过该机制，RNAi机制协调siRNA的靶向确定的定位和相应的RNAi活性，并且还提供了直接在细胞核中形成核程序化活性RNA诱导沉默复合物的证据。
Recent observations of RNA interference (RNAi) in the nuclei of human cells raise key questions about the extent to which nuclear and cytoplasmic RNAi pathways are shared. By directly visualizing the localization of small interfering RNA (siRNA) in live human cells, we show here that siRNA either selectively localizes in the cytoplasm or translocates into the nucleus, depending on where the silencing target RNA resides. Two siRNAs that target the small nuclear 7SK and U6 RNAs localize into the nucleus as duplexes. In contrast, an siRNA targeting the cytoplasmic hepatitis C virus replicon RNA dissociates, and only antisense strand distributes in the cytoplasm of the cells harboring the target RNA, whereas sense strand gets degraded. At the same time, both strands of the latter siRNA are distributed throughout the cytoplasm and nucleus in cells lacking the silencing target RNA. These results suggest the existence of a mechanism by which the RNAi machinery orchestrates a target-determined localization of the siRNA and the corresponding RNAi activity, and also provide evidence for formation of nuclear-programmed active RNA induced silencing complexes directly in the nucleus.