title: Genome-wide identification of Fas/CD95 alternative splicing regulators reveals links with iron homeostasis.
abstract: Alternative splicing of Fas/CD95 exon 6 generates either a membrane-bound receptor that promotes, or a soluble isoform that inhibits, apoptosis. Using an automatized genome-wide siRNA screening for alternative splicing regulators of endogenous transcripts in mammalian cells, we identified 200 genes whose knockdown modulates the ratio between Fas/CD95 isoforms. These include classical splicing regulators; core spliceosome components; and factors implicated in transcription and chromatin remodeling, RNA transport, intracellular signaling, and metabolic control. Coherent effects of genes involved in iron homeostasis and pharmacological modulation of iron levels revealed a link between intracellular iron and Fas/CD95 exon 6 inclusion. A splicing regulatory network linked iron levels with reduced activity of the Zinc-finger-containing splicing regulator SRSF7, and in vivo and in vitro assays revealed that iron inhibits SRSF7 RNA binding. Our results uncover numerous links between cellular pathways and RNA processing and a mechanism by which iron homeostasis can influence alternative splicing.
authors.affiliation: Centre de Regulació Genòmica, Dr. Aiguader 88, 08003 Barcelona, Spain; Universitat Pompeu Fabra, Dr. Aiguader 88, 08003 Barcelona, Spain.
authors.forename: J Ramón
authors.initials: JR
authors.lastname: Tejedor
authors.affiliation: Centre de Regulació Genòmica, Dr. Aiguader 88, 08003 Barcelona, Spain; Universitat Pompeu Fabra, Dr. Aiguader 88, 08003 Barcelona, Spain.
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Papasaikas
authors.affiliation: Centre de Regulació Genòmica, Dr. Aiguader 88, 08003 Barcelona, Spain; Universitat Pompeu Fabra, Dr. Aiguader 88, 08003 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats, Pg Lluis Companys, 23, 08003 Barcelona, Spain. Electronic address: juan.valcarcel@crg.eu.
authors.forename: Juan
authors.initials: J
authors.lastname: Valcárcel
mesh_terms: D017398:Alternative Splicing; D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins; D001665:Binding Sites; D049109:Cell Proliferation / Q000187:drug effects; D003676:Deferoxamine / Q000494:pharmacology; D005091:Exons; D053263:Gene Regulatory Networks; D016678:Genome; D055106:Genome-Wide Association Study; D006367:HeLa Cells; D006706:Homeostasis; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D007438:Introns; D007501:Iron / Q000378:metabolism* / Q000494:pharmacology; D007502:Iron Chelating Agents / Q000494:pharmacology; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D058977:Molecular Sequence Annotation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D020033:Protein Isoforms / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D000068103:Serine-Arginine Splicing Factors; D017381:Spliceosomes / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D019014:fas Receptor / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism
chemical_list: D051017:Apoptosis Regulatory Proteins; C412403:DIABLO protein, human; D047908:Intracellular Signaling Peptides and Proteins; D007502:Iron Chelating Agents; D024101:Mitochondrial Proteins; D009687:Nuclear Proteins; D020033:Protein Isoforms; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D019014:fas Receptor; D000068103:Serine-Arginine Splicing Factors; D007501:Iron; D003676:Deferoxamine