title: Regulation of FAS exon definition and apoptosis by the Ewing sarcoma protein.
abstract: The Ewing sarcoma protein EWS is an RNA and DNA binding protein implicated in transcription, pre-mRNA splicing, and DNA damage response. Using CLIP-seq, we identified EWS RNA binding sites in exonic regions near 5' splice sites. A prominent target was exon 6 of the FAS/CD95 receptor, which is alternatively spliced to generate isoforms with opposing activities in programmed cell death. Depletion and overexpression experiments showed that EWS promotes exon 6 inclusion and consequently the synthesis of the proapoptotic FAS/CD95 isoform, whereas an EWS-FLI1 fusion protein characteristic of Ewing sarcomas shows decreased activity. Biochemical analyses revealed that EWS binding promotes the recruitment of U1snRNP and U2AF65 to the splice sites flanking exon 6 and therefore exon definition. Consistent with a role for EWS in the regulation of programmed cell death, cells depleted of EWS show decreased sensitivity to FAS-induced apoptosis, and elevated EWS expression enhances apoptosis in EWS-haploinsufficient Ewing sarcoma cells.
authors.affiliation: Centre for Genomic Regulation, carrer Doctor Aiguader 88, 08003 Barcelona, Spain; University of Rome "Foro Italico," Piazza Lauro de Bosis 6, 00135 Rome, Italy; Laboratories of Cellular and Molecular Neurobiology and of Neuroimmunology, Fondazione Santa Lucia, 00143 Rome, Italy. Electronic address: mariapaola.paronetto@uniroma4.it.
authors.forename: Maria Paola
authors.initials: MP
authors.lastname: Paronetto
authors.affiliation: Universitat Pompeu Fabra, carrer Doctor Aiguader 88, 08003 Barcelona, Spain.
authors.forename: Isabella
authors.initials: I
authors.lastname: Bernardis
authors.affiliation: Laboratories of Cellular and Molecular Neurobiology and of Neuroimmunology, Fondazione Santa Lucia, 00143 Rome, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Volpe
authors.affiliation: Centre for Genomic Regulation, carrer Doctor Aiguader 88, 08003 Barcelona, Spain; Universitat Pompeu Fabra, carrer Doctor Aiguader 88, 08003 Barcelona, Spain.
authors.forename: Elias
authors.initials: E
authors.lastname: Bechara
authors.affiliation: Universitat Pompeu Fabra, carrer Doctor Aiguader 88, 08003 Barcelona, Spain.
authors.forename: Endre
authors.initials: E
authors.lastname: Sebestyén
authors.affiliation: Universitat Pompeu Fabra, carrer Doctor Aiguader 88, 08003 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats, Pg Lluis Companys 23, 08010 Barcelona, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Eyras
authors.affiliation: Centre for Genomic Regulation, carrer Doctor Aiguader 88, 08003 Barcelona, Spain; Universitat Pompeu Fabra, carrer Doctor Aiguader 88, 08003 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats, Pg Lluis Companys 23, 08010 Barcelona, Spain. Electronic address: juan.valcarcel@crg.eu.
authors.forename: Juan
authors.initials: J
authors.lastname: Valcárcel
mesh_terms: D017398:Alternative Splicing; D017209:Apoptosis / Q000235:genetics*; D045744:Cell Line, Tumor; D005091:Exons; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000378:metabolism; D051789:Proto-Oncogene Protein c-fli-1 / Q000235:genetics / Q000378:metabolism; D034802:RNA-Binding Protein EWS / Q000235:genetics / Q000378:metabolism; D012512:Sarcoma, Ewing / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D015398:Signal Transduction; D019014:fas Receptor / Q000235:genetics*
chemical_list: C106031:EWS-FLI fusion protein; C491901:FAS protein, human; D015514:Oncogene Proteins, Fusion; D051789:Proto-Oncogene Protein c-fli-1; D034802:RNA-Binding Protein EWS; D019014:fas Receptor