title: NSrp70 is a novel nuclear speckle-related protein that modulates alternative pre-mRNA splicing in vivo.
abstract: Nuclear speckles are known to be the storage sites of mRNA splicing regulators. We report here the identification and characterization of a novel speckle protein, referred to as NSrp70, based on its subcellular localization and apparent molecular weight. This protein was first identified as CCDC55 by the National Institutes of Health Mammalian Gene Collection, although its function has not been assigned. NSrp70 was colocalized and physically interacted with SC35 and ASF/SF2 in speckles. NSrp70 has a putative RNA recognition motif, the RS-like region, and two coiled-coil domains, suggesting a role in RNA processing. Accordingly, using CD44, Tra2β1 and Fas constructs as splicing reporter minigenes, we found that NSrp70 modulated alternative splice site selection in vivo. The C-terminal 10 amino acids (531-540), including (536)RD(537), were identified as a novel nuclear localization signal, and the region spanning 290-471 amino acids was critical for speckle localization and binding to SC35 and ASF/SF2. The N-terminal region (107-161) was essential for the pre-mRNA splicing activity. Finally, we found that knockout of NSrp70 gene in mice led to a lack of progeny, including fetal embryos. Collectively, we demonstrate that NSrp70 is a novel splicing regulator and essentially required early stage of embryonic development.
authors.affiliation: School of Life Sciences, Cell Dynamics Research Center, and Immune Synapse Research Center, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea.
authors.forename: Young-Dae
authors.initials: YD
authors.lastname: Kim
authors.forename: Jung-Yoon
authors.initials: JY
authors.lastname: Lee
authors.forename: Kyu-Man
authors.initials: KM
authors.lastname: Oh
authors.forename: Masatake
authors.initials: M
authors.lastname: Araki
authors.forename: Kimi
authors.initials: K
authors.lastname: Araki
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Yamamura
authors.forename: Chang-Duk
authors.initials: CD
authors.lastname: Jun
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D002460:Cell Line; D022003:Cell Nucleus Structures / Q000737:chemistry; D005804:Genes, Lethal; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D009687:Nuclear Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D017434:Protein Structure, Tertiary; D012322:RNA Precursors / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism; D000068103:Serine-Arginine Splicing Factors
chemical_list: C560091:NSRP1 protein, human; D009687:Nuclear Proteins; D012322:RNA Precursors; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D000068103:Serine-Arginine Splicing Factors