title: Son is essential for nuclear speckle organization and cell cycle progression.
abstract: Subnuclear organization and spatiotemporal regulation of pre-mRNA processing factors is essential for the production of mature protein-coding mRNAs. We have discovered that a large protein called Son has a novel role in maintaining proper nuclear organization of pre-mRNA processing factors in nuclear speckles. The primary sequence of Son contains a concentrated region of multiple unique tandem repeat motifs that may support a role for Son as a scaffolding protein for RNA processing factors in nuclear speckles. We used RNA interference (RNAi) approaches and high-resolution microscopy techniques to study the functions of Son in the context of intact cells. Although Son precisely colocalizes with pre-mRNA splicing factors in nuclear speckles, its depletion by RNAi leads to cell cycle arrest in metaphase and causes dramatic disorganization of small nuclear ribonuclear protein and serine-arginine rich protein splicing factors during interphase. Here, we propose that Son is essential for appropriate subnuclear organization of pre-mRNA splicing factors and for promoting normal cell cycle progression.
authors.affiliation: Biomedical Sciences Ph.D. Program, Department of Biological Sciences, Wright State University, Dayton, OH 45435, USA.
authors.forename: Alok
authors.initials: A
authors.lastname: Sharma
authors.forename: Hideaki
authors.initials: H
authors.lastname: Takata
authors.forename: Kei-ichi
authors.initials: K
authors.lastname: Shibahara
authors.forename: Athanasios
authors.initials: A
authors.lastname: Bubulya
authors.forename: Paula A
authors.initials: PA
authors.lastname: Bubulya
mesh_terms: D000595:Amino Acid Sequence; D002453:Cell Cycle / Q000502:physiology*; D002467:Cell Nucleus / Q000378:metabolism* / Q000648:ultrastructure; D002470:Cell Survival; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D015778:Minor Histocompatibility Antigens; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D000068103:Serine-Arginine Splicing Factors
chemical_list: C459802:CASC3 protein, human; D004268:DNA-Binding Proteins; D015778:Minor Histocompatibility Antigens; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D012322:RNA Precursors; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; C088203:SON protein, human; D000068103:Serine-Arginine Splicing Factors