Two PABPC1-binding sites in GW182 proteins promote miRNA-mediated gene silencing.
Two PABPC1-binding sites in GW182 proteins promote miRNA-mediated gene silencing.
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DOI：
10.1038/emboj.2010.274
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发表时间：
2010-12-15
期刊：
影响因子：
11.4
通讯作者：
Izaurralde, Elisa
中科院分区：
文献类型：
--
作者：
Huntzinger, Eric;Braun, Joerg E.;Heimstaedt, Susanne;Zekri, Latifa;Izaurralde, Elisa
先前的研究表明，miRNA介导的沉默机制可能在人类和果蝇细胞之间存在差异。在此，直接比较表明该机制是保守的，并且GW 182-PABP相互作用是体内沉默所需的。miRNA介导的基因沉默需要GW 182蛋白，其特征在于与Argonaute蛋白（AGO）相互作用的N-末端结构域和C-末端沉默结构域（SD）。在黑腹果蝇（Drosophila melanogaster，Dm）GW 182和人类（Hs）直系同源物TNRC 6C中，SD先前被证明与细胞质多聚腺苷酸结合蛋白（PABPC 1）相互作用。在这里，我们发现GW 182蛋白的两个区域与PABPC 1相互作用：第一个区域包含PABP相互作用基序2（PAM 2;如前所示的TNRC 6C），第二个区域包含SD中的M2和C末端序列。后者介导与PABPC 1 N-末端结构域的间接结合。In D.在黑腹细胞中，第二个结合位点占主导地位;然而，在HsTNRC 6A-C中，PAM 2基序对于与Hs和DmPABPC 1结合是必需的。因此，TNRC 6A-C PAM 2基序中的单个氨基酸取代消除了与PABPC 1的相互作用。该突变还损害TNRC 6s沉默活性。我们的研究结果表明，尽管PABPC 1结合位点的相对强度存在物种特异性差异，但GW 182蛋白和PABPC 1之间的相互作用对于动物细胞中miRNA介导的沉默至关重要。
Previous studies have suggested that the mechanism of miRNA-mediated silencing may differ between human and Drosophila cells. Here, a direct comparison demonstrates that the mechanism is conserved and the GW182–PABP interaction is required for silencing in vivo. miRNA-mediated gene silencing requires the GW182 proteins, which are characterized by an N-terminal domain that interacts with Argonaute proteins (AGOs), and a C-terminal silencing domain (SD). In Drosophila melanogaster (Dm) GW182 and a human (Hs) orthologue, TNRC6C, the SD was previously shown to interact with the cytoplasmic poly(A)-binding protein (PABPC1). Here, we show that two regions of GW182 proteins interact with PABPC1: the first contains a PABP-interacting motif 2 (PAM2; as shown before for TNRC6C) and the second contains the M2 and C-terminal sequences in the SD. The latter mediates indirect binding to the PABPC1 N-terminal domain. In D. melanogaster cells, the second binding site dominates; however, in HsTNRC6A–C the PAM2 motif is essential for binding to both Hs and DmPABPC1. Accordingly, a single amino acid substitution in the TNRC6A–C PAM2 motif abolishes the interaction with PABPC1. This mutation also impairs TNRC6s silencing activity. Our findings reveal that despite species-specific differences in the relative strength of the PABPC1-binding sites, the interaction between GW182 proteins and PABPC1 is critical for miRNA-mediated silencing in animal cells.
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影响因子：
11.4
作者：
Behm-Ansmant, Isabelle;Gatfield, David;Izaurralde, Elisa
通讯作者：
Izaurralde, Elisa
影响因子：
4.5
作者：
Walters, Robert W.;Bradrick, Shelton S.;Gromeier, Matthias
通讯作者：
Gromeier, Matthias
DOI：
10.1073/pnas.0603701103
发表时间：
2006-06-20
影响因子：
11.1
作者：
Karim, Muhammad M.;Svitkin, Yuri V.;Sonenberg, Nahum
通讯作者：
Sonenberg, Nahum
影响因子：
5.3
作者：
Ezzeddine, Nader;Chang, Tsung-Cheng;Shyu, Ann-Bin
通讯作者：
Shyu, Ann-Bin
影响因子：
56.9
作者：
Pillai, RS;Bhattacharyya, SN;Filipowicz, W
通讯作者：
Filipowicz, W