title: XE7: a novel splicing factor that interacts with ASF/SF2 and ZNF265.
abstract: Pre-mRNA splicing is performed by the spliceosome. SR proteins in this macromolecular complex are essential for both constitutive and alternative splicing. By using the SR-related protein ZNF265 as bait in a yeast two-hybrid screen, we pulled out the uncharacterized human protein XE7, which is encoded by a pseudoautosomal gene. XE7 had been identified in a large-scale proteomic analysis of the human spliceosome. It consists of two different isoforms produced by alternative splicing. The arginine/serine (RS)-rich region in the larger of these suggests a role in mRNA processing. Herein we show for the first time that XE7 is an alternative splicing regulator. XE7 interacts with ZNF265, as well as with the essential SR protein ASF/SF2. The RS-rich region of XE7 dictates both interactions. We show that XE7 localizes in the nucleus of human cells, where it colocalizes with both ZNF265 and ASF/SF2, as well as with other SR proteins, in speckles. We also demonstrate that XE7 influences alternative splice site selection of pre-mRNAs from CD44, Tra2-beta1 and SRp20 minigenes. We have thus shown that the spliceosomal component XE7 resembles an SR-related splicing protein, and can influence alternative splicing.
authors.affiliation: Basic & Clinical Genomics Laboratory, School of Medical Sciences and Bosch Institute, The University of Sydney, NSW 2006, Australia.
authors.forename: A Helena
authors.initials: AH
authors.lastname: Mangs
authors.forename: Helen J L
authors.initials: HJ
authors.lastname: Speirs
authors.forename: Christine
authors.initials: C
authors.lastname: Goy
authors.forename: David J
authors.initials: DJ
authors.lastname: Adams
authors.forename: M Andrea
authors.initials: MA
authors.lastname: Markus
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Morris
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000941:Antigens / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D006801:Humans; D008562:Membrane Glycoproteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D016601:RNA-Binding Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D016415:Sequence Alignment; D000068103:Serine-Arginine Splicing Factors; D020798:Two-Hybrid System Techniques
chemical_list: D000941:Antigens; D008562:Membrane Glycoproteins; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; C486373:ZRANB2 protein, human; C077916:AKAP17A protein, human; D000068103:Serine-Arginine Splicing Factors