title: The RNA-binding protein Rbfox2: an essential regulator of EMT-driven alternative splicing and a mediator of cellular invasion.
abstract: The epithelial-mesenchymal transition (EMT), a prerequisite for cancer progression and metastasis formation, is regulated not only at the transcriptional but also at the post-transcriptional level, including at the level of alternative pre-mRNA splicing. Several recent studies have highlighted the involvement of splicing factors, including epithelial splicing regulatory proteins (Esrps) and RNA-binding Fox protein 2 (Rbfox2), in this process. Esrps regulate epithelial-specific splicing, and their expression is downregulated during EMT. By contrast, the role of Rbfox2 is controversial because Rbfox2 regulates epithelial as well as mesenchymal splicing events. Here, we have used several established cell culture models to investigate the functions of Rbfox2 during EMT. We demonstrate that induction of an EMT upregulates the expression of Rbfox2, which correlates with an increase in Rbfox2-regulated splicing events in the cortactin (Cttn), Pard3 and dynamin 2 (Dnm2) transcripts. At the same time, however, the epithelial-specific ability to splice the Enah, Slk and Tsc2 transcripts is either reduced or lost completely by Rbfox2, which might be due, in part, to downregulation of the expression of the Esrps cooperative factors. Depletion of Rbfox2 during EMT did not prevent the activation of transforming growth factor-β signaling, the upregulation of mesenchymal markers or changes in cell morphology toward a mesenchymal phenotype. In addition, this depletion did not influence cell migration. However, depletion of Rbfox2 in cells that have completed an EMT significantly reduced their invasive potential. Taken together, our results suggest that during an EMT, Rbfox2-regulated splicing shifts from epithelial-to mesenchymal-specific events, leading to a higher degree of tissue invasiveness.
authors: Department of Molecular Embryology, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.
authors: C
authors: C
authors: Braeutigam
authors: Department of Molecular Embryology, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.
authors: L
authors: L
authors: Rago
authors: Department of Molecular Embryology, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.
authors: A
authors: A
authors: Rolke
authors: Department of Biomedicine, University of Basel, Basel, Switzerland.
authors: L
authors: L
authors: Waldmeier
authors: Department of Biomedicine, University of Basel, Basel, Switzerland.
authors: G
authors: G
authors: Christofori
authors: 1] Department of Molecular Embryology, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany [2] Institute of Human Genetics, University Medical Center of the Johannes Gutenberg, University of Mainz, Mainz, Germany.
authors: J
authors: J
authors: Winter
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D015536:Down-Regulation / Q000235:genetics; D004847:Epithelial Cells / Q000378:metabolism; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics*; D051379:Mice; D009361:Neoplasm Invasiveness / Q000235:genetics*; D012326:RNA Splicing / Q000235:genetics*; D000072260:RNA Splicing Factors; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D015854:Up-Regulation / Q000235:genetics
chemical_list: D000072260:RNA Splicing Factors; D016601:RNA-Binding Proteins; C558929:Rbfox2 protein, mouse