Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
Nucleic Acids Res. 2009 Dec;37(22):7533-45. doi: 10.1093/nar/gkp812.
Mammalian Argonaute 2 (Ago2) protein associates with microRNAs (miRNAs) or small interfering RNAs (siRNAs) forming RNA-induced silencing complexes (RISCs/miRNPs). In the present work, we characterize the RNA-binding and nucleolytic activity of recombinant mouse Ago2. Our studies show that recombinant mouse Ago2 binds efficiently to miRNAs forming active RISC. Surprisingly, we find that recombinant mouse Ago2 forms active RISC using pre-miRNAs or long unstructured single stranded RNAs as guides. Furthermore, we demonstrate that, in vivo, endogenous human Ago2 binds directly to pre-miRNAs independently of Dicer, and that Ago2:pre-miRNA complexes are found both in the cytoplasm and in the nucleus of human cells.
哺乳动物 Argonaute 2（Ago2）蛋白与 microRNAs（miRNAs）或 small interfering RNAs（siRNAs）结合形成 RNA 诱导的沉默复合物（RISCs/miRNPs）。在本工作中，我们对重组小鼠 Ago2 的 RNA 结合和核酸酶活性进行了表征。我们的研究表明，重组小鼠 Ago2 可以有效地与 miRNA 结合形成有活性的 RISCs。令人惊讶的是，我们发现重组小鼠 Ago2 可以使用前体 miRNA 或长未折叠的单链 RNA 作为向导形成有活性的 RISCs。此外，我们证明，内源性人 Ago2 可以不依赖于 Dicer 直接与 pre-miRNA 结合，并且 Ago2:pre-miRNA 复合物可以在人细胞的细胞质和细胞核中都被发现。
