Ago-TNRC6 triggers microRNA-mediated decay by promoting two deadenylation steps.
Ago-TNRC6 triggers microRNA-mediated decay by promoting two deadenylation steps.
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DOI：
10.1038/nsmb.1709
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发表时间：
2009-11
影响因子：
16.8
通讯作者：
中科院分区：
文献类型：
--
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MicroRNAs （miRNAs）主要通过促进mRNA衰变来抑制其靶mRNA的表达。哺乳动物细胞中mirna介导的衰变的机制、动力学和参与酶在很大程度上仍不清楚。结合转录脉冲、rna拴链、显性阴性突变体过表达和sirna介导的基因敲低等方法，我们发现let-7 mirna诱导的沉默复合物（miRISCs）含有Argonaute （Ago）和TNRC6（也称为GW182）蛋白，在哺乳动物细胞中通过诱导Pan2-Pan3和Ccr4-Caf1 deadenylase复合物介导的加速双相死蛋白化，然后在Dcp1-Dcp2复合物的指导下脱壳，从而引发高度快速的mRNA衰变。当与mrna连接时，所有四种人类Ago蛋白和TNRC6C都能够重现这两个死基化步骤。两个保守的人类Ago2苯丙氨酸（F470和F505）在招募TNRC6促进死蛋白化中起关键作用。这些发现表明，促进双相deadenylation以触发mRNA衰变是miRISCs的内在特性。
MicroRNAs (miRNAs) silence the expression of their mRNA targets mainly through promoting mRNA decay. The mechanism, kinetics and participating enzymes for miRNA-mediated decay in mammalian cells remain largely unclear. Combining the approaches of transcriptional pulsing, RNA-tethering, over-expression of dominant-negative mutants, and siRNA-mediated gene knockdown, we show that let-7 miRNA-induced silencing complexes (miRISCs), which contain Argonaute (Ago) and TNRC6 (also known as GW182) proteins, trigger highly rapid mRNA decay by inducing accelerated biphasic deadenylation mediated via Pan2-Pan3 and Ccr4-Caf1 deadenylase complexes followed by Dcp1-Dcp2 complex-directed decapping in mammalian cells. When tethered to mRNAs, all four human Ago proteins and TNRC6C are each able to recapitulate the two deadenylation steps. Two conserved human Ago2 phenylalanines (F470 and F505) are critical for recruiting TNRC6 to promote deadenylation. These findings indicate that promoting biphasic deadenylation to trigger mRNA decay is an intrinsic property of miRISCs.
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影响因子：
64.8
作者：
Baek, Daehyun;Villen, Judit;Shin, Chanseok;Camargo, Fernando D.;Gygi, Steven P.;Bartel, David P.
通讯作者：
Bartel, David P.
影响因子：
21.3
作者：
Jakymiw, A;Lian, SL;Chan, EKL
通讯作者：
Chan, EKL
影响因子：
64.5
作者：
Kiriakidou, Marianthi;Tan, Grace S.;Mourelatos, Zissimos
通讯作者：
Mourelatos, Zissimos
影响因子：
56.9
作者：
Giraldez, AJ;Mishima, Y;Schier, AF
通讯作者：
Schier, AF
影响因子：
5.3
作者：
Baillat, David;Shiekhattar, Ramin
通讯作者：
Shiekhattar, Ramin