title: The second open reading frame of the avian reovirus S1 gene encodes a transcription-dependent and CRM1-independent nucleocytoplasmic shuttling protein.
abstract: It was previously shown that the second open reading frame of the avian reovirus S1 gene encodes a 146-amino-acid nonstructural protein, designated p17, which has no known function and no sequence similarity to other known proteins. The results presented in this report demonstrate that p17 accumulates in the nucleoplasm of infected and transfected cells. An examination of the deduced amino acid sequence of p17 revealed the presence of a putative monopartite nuclear localization signal (NLS) between residues 119 and 128. Mutagenesis analysis revealed both that this sequence is indeed a functional NLS and that two of its basic residues are critical for the normal nuclear distribution of p17. An interspecies heterokaryon assay further showed that p17 shuttles continuously between the nucleus and the cytoplasm and that this activity is restricted to its NLS-containing C-terminal tail. Finally, an analysis of the intracellular distribution of p17 in the presence of inhibitors of both RNA polymerase II and CRM1 further revealed that the nucleocytoplasmic distribution of p17 is coupled to transcriptional activity and that the viral protein exits the nucleus via a CRM1-independent pathway.
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: Celina
authors.initials: C
authors.lastname: Costas
authors.forename: José
authors.initials: J
authors.lastname: Martínez-Costas
authors.forename: Gustavo
authors.initials: G
authors.lastname: Bodelón
authors.forename: Javier
authors.initials: J
authors.lastname: Benavente
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D005796:Genes / Q000235:genetics*; D016679:Genome, Viral; D028884:Karyopherins / Q000378:metabolism*; D029543:Nucleocytoplasmic Transport Proteins / Q000235:genetics*; D016366:Open Reading Frames; D030101:Orthoreovirus, Avian / Q000235:genetics*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D014158:Transcription, Genetic / Q000502:physiology*; D017361:Viral Nonstructural Proteins / Q000235:genetics; D000097606:Exportin 1 Protein
chemical_list: D028884:Karyopherins; D029543:Nucleocytoplasmic Transport Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D017361:Viral Nonstructural Proteins; D000097606:Exportin 1 Protein