Identification of a signature motif for the eIF4a3-SECIS interaction.
Identification of a signature motif for the eIF4a3-SECIS interaction.
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DOI：
10.1093/nar/gkr446
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发表时间：
2011-09-01
影响因子：
14.9
通讯作者：
Driscoll DM
中科院分区：
文献类型：
--
作者：
Budiman ME;Bubenik JL;Driscoll DM
EIF4a3是一个死盒蛋白家族成员，是外显子连接复合体的一个组成部分，它组装在剪接的mRNAs上。在缺硒期间，该蛋白还可以作为硒蛋白合成的转录选择性翻译抑制因子。硒半胱氨酸(Sec)掺入硒蛋白需要在3‘非翻译区有Sec插入序列(SECIS)元件。在缺硒期间，eIF4a3从非必需的硒蛋白中结合SECIS元件，阻止SEC插入。我们利用RNA凝胶位移、表面等离子体共振和酶足迹技术确定了eIF4a3-SECIS相互作用的分子特征。我们的结果支持一个双部位相互作用模型，其中eIF4a3结合了SECIS的内部环和顶环。此外，络合物的稳定性需要SECIS核心中的尿苷。在蛋白质需求方面，eIF4a3的两个球状结构域由连接子连接，都是SECIS结合的关键。与全长eIF4a3相比，反式结合的两个结构域的结合率较低，但值得注意的是，尿苷对络合物的稳定性不再重要。这些结果为eIF4a3如何区分SECIS元件并抑制翻译提供了深入的见解。
eIF4a3, a DEAD-box protein family member, is a component of the exon junction complex which assembles on spliced mRNAs. The protein also acts as a transcript-selective translational repressor of selenoprotein synthesis during selenium deficiency. Selenocysteine (Sec) incorporation into selenoproteins requires a Sec Insertion Sequence (SECIS) element in the 3′ untranslated region. During selenium deficiency, eIF4a3 binds SECIS elements from non-essential selenoproteins, preventing Sec insertion. We identified a molecular signature for the eIF4a3-SECIS interaction using RNA gel shifts, surface plasmon resonance and enzymatic foot printing. Our results support a two-site interaction model, where eIF4a3 binds the internal and apical loops of the SECIS. Additionally, the stability of the complex requires uridine in the SECIS core. In terms of protein requirements, the two globular domains of eIF4a3, which are connected by a linker, are both critical for SECIS binding. Compared to full-length eIF4a3, the two domains in trans bind with a lower association rate but notably, the uridine is no longer important for complex stability. These results provide insight into how eIF4a3 discriminates among SECIS elements and represses translation.
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影响因子：
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作者：
Fagegaltier, D;Lescure, A;Krol, A
通讯作者：
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影响因子：
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