A retained intron in the 3′-UTR of Calm3 mRNA mediates its Staufen2-and activity-dependent localization to neuronal dendrites
A retained intron in the 3′-UTR of Calm3 mRNA mediates its Staufen2-and activity-dependent localization to neuronal dendrites
复制标题
DOI：
10.15252/embr.201744334
复制
发表时间：
2017-10-01
期刊：
影响因子：
7.7
通讯作者：
Kiebler, Michael A.
中科院分区：
文献类型：
--
作者：
Sharangdhar, Tejaswini;Sugimoto, Yoichiro;Kiebler, Michael A.
树突状细胞的定位和局部信使核糖核酸的翻译有助于神经元的突触可塑性。Staufen2(Stau2)是一种广为人知的神经元双链RNA结合蛋白(DsRBP)，与树突状细胞的mRNA定位有关。Stau2与其靶mRNAs结合的特异性仍然难以捉摸。使用单核苷酸分辨片段(ICLIP)，我们发现显著增强了Stau2与356个转录本的3-UTRs的结合。其中28例(7.9%)与其3-UTR中保留的内含子结合。结合最强的3-UTR内含子存在于钙调蛋白3(CalM3(L))的最长亚型。CalM3(L)3-非编码区含有6个Stau2交联簇，其中4个位于该保留的3-非编码区内含子中。CalM3(L)基因定位于神经元树突，而3-UTR内含子的缺失影响了其树突的定位。重要的是，Stau2通过3-UTR内含子介导这种树突定位，而不影响其稳定性。此外，N-甲基-D-天冬氨酸介导的突触活性特异性地促进了CalM3(L)亚型的树突状基因的定位，而抑制突触活性则显著降低了它的定位。综上所述，我们的结果确定保留的内含子是招募STANU2的关键元件，这使得CalM3(L)mRNAs能够定位到远端的树突。
Dendritic localization and hence local mRNA translation contributes to synaptic plasticity in neurons. Staufen2 (Stau2) is a well-known neuronal double-stranded RNA-binding protein (dsRBP) that has been implicated in dendritic mRNA localization. The specificity of Stau2 binding to its target mRNAs remains elusive. Using individual-nucleotide resolution CLIP (iCLIP), we identified significantly enriched Stau2 binding to the 3-UTRs of 356 transcripts. In 28 (7.9%) of those, binding occurred to a retained intron in their 3-UTR. The strongest bound 3-UTR intron was present in the longest isoform of Calmodulin 3 (Calm3(L)) mRNA. Calm3(L) 3-UTR contains six Stau2 crosslink clusters, four of which are in this retained 3-UTR intron. The Calm3(L) mRNA localized to neuronal dendrites, while lack of the 3-UTR intron impaired its dendritic localization. Importantly, Stau2 mediates this dendritic localization via the 3-UTR intron, without affecting its stability. Also, NMDA-mediated synaptic activity specifically promoted the dendritic mRNA localization of the Calm3(L) isoform, while inhibition of synaptic activity reduced it substantially. Together, our results identify the retained intron as a critical element in recruiting Stau2, which then allows for the localization of Calm3(L) mRNA to distal dendrites.