RBM47-regulated alternative splicing of TJP1 promotes actin stress fiber assembly during epithelial-to-mesenchymal transition
RBM47-regulated alternative splicing of TJP1 promotes actin stress fiber assembly during epithelial-to-mesenchymal transition
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DOI：
10.1038/s41388-019-0892-5
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发表时间：
2019-09-19
期刊：
影响因子：
8
通讯作者：
Kim, Kee K.
中科院分区：
文献类型：
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作者：
Kim, Yong-Eun;Won, Minho;Kim, Kee K.
在上皮-间质转化（EMT）过程中细胞的形态和功能变化已知是由选择性剪接调节的。然而，只有少数剪接因子参与EMT已被报道，其潜在的机制仍然在很大程度上未知。在这里，我们发现缺乏外显子20的紧密连接蛋白1（TJP 1）的亚型（TJP 1-α-）主要在肿瘤组织和A549细胞中表达，在转化生长因子-β（TGF-β诱导的EMT）中。RBM 47促进了TJP 1的外显子20的包含，该外显子编码a结构域，RBM 47通过该结构域识别外显子20的下游内含子区域中的（U）GCAUG。我们还发现RBM 47的第一个RNA识别基序（RRM）结构域在调节选择性剪接及其识别TJP 1的前体mRNA中至关重要。此外，我们证明了TJP 1-α-同种型增强了肌动蛋白应力纤维的组装，从而在伤口愈合试验中促进细胞迁移。我们的研究结果提示了RBM 47在EMT过程中对TJP 1前体mRNA选择性剪接的调控机制，为研究选择性剪接对EMT的调控提供了基础。
Morphological and functional changes in cells during the epithelial-mesenchymal transition (EMT) process are known to be regulated by alternative splicing. However, only a few splicing factors involved in EMT have been reported and their underlying mechanisms remain largely unknown. Here, we showed that an isoform of tight junction protein 1 (TJP1) lacking exon 20 (TJP1-alpha-) is predominantly expressed in tumor tissues and in A549 cells during transforming growth factor-beta (TGF-beta-induced EMT. RBM47 promoted the inclusion of exon 20 of TJP1, the alternative exon encoding the a-domain, by which RBM47 recognizes to (U)GCAUG in the downstream intronic region of exon 20. We also found that the first RNA recognition motif (RRM) domain of RBM47 is critical in the regulation of alternative splicing and its recognition to pre-mRNA of TJP1. Furthermore, we demonstrated that the TJP1-alpha- isoform enhances the assembly of actin stress fibers, thereby promoting cellular migration in a wound healing assay. Our results suggest the regulatory mechanism for the alternative splicing of TJP1 pre-mRNA by RBM47 during EMT, providing a basis for studies related to the modulation of EMT via alternative splicing.