Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), 27100 Pavia, Italy.
J Cell Biol. 2010 Oct 4;191(1):87-99. doi: 10.1083/jcb.201001073. Epub 2010 Sep 27.
Epithelial-to-mesenchymal transition (EMT) and its reversal (MET) are crucial cell plasticity programs that act during development and tumor metastasis. We have previously shown that the splicing factor and proto-oncogene SF2/ASF impacts EMT/MET through production of a constitutively active splice variant of the Ron proto-oncogene. Using an in vitro model, we now show that SF2/ASF is also regulated during EMT/MET by alternative splicing associated with the nonsense-mediated mRNA decay pathway (AS-NMD). Overexpression and small interfering RNA experiments implicate the splicing regulator Sam68 in AS-NMD of SF2/ASF transcripts and in the choice between EMT/MET programs. Moreover, Sam68 modulation of SF2/ASF splicing appears to be controlled by epithelial cell-derived soluble factors that act through the ERK1/2 signaling pathway to regulate Sam68 phosphorylation. Collectively, our results reveal a hierarchy of splicing factors that integrate splicing decisions into EMT/MET programs in response to extracellular stimuli.
上皮-间充质转化 (EMT) 及其逆转 (MET) 是发育和肿瘤转移过程中至关重要的细胞可塑性程序。我们之前已经表明，剪接因子和原癌基因 SF2/ASF 通过产生 Ron 原癌基因的组成性激活剪接变体来影响 EMT/MET。现在，我们使用体外模型表明，SF2/ASF 也通过与无意义介导的 mRNA 降解途径 (AS-NMD) 相关的选择性剪接受到 EMT/MET 的调控。过表达和小干扰 RNA 实验表明剪接调节剂 Sam68 参与了 SF2/ASF 转录本的 AS-NMD 以及 EMT/MET 程序之间的选择。此外，Sam68 对 SF2/ASF 剪接的调节似乎受到上皮细胞衍生的可溶性因子的控制，这些因子通过 ERK1/2 信号通路发挥作用，以调节 Sam68 的磷酸化。总的来说，我们的结果揭示了一系列剪接因子，它们将剪接决策整合到 EMT/MET 程序中，以响应细胞外刺激。
