title: A novel nucleocytoplasmic shuttling sequence of DAZAP1, a testis-abundant RNA-binding protein.
abstract: Deleted in Azoospermia Associated Protein 1 (DAZAP1) is a ubiquitous RNA-binding protein highly expressed in the human and the mouse testes. It shows a dynamic subcellular localization during spermatogenesis, present predominantly in the nuclei of late-stage spermatocytes and round spermatids and translocated to the cytoplasm during spermatid elongation. To test the hypothesis that DAZAP1 shuttles between the nucleus and the cytoplasm, we studied the nuclear transport of DAZAP1 in somatic cells using immunostaining, heterokaryon formation, and mutagenesis. DAZAP1 is detected exclusively in the nucleus and has the ability to shuttle between the nucleus and the cytoplasm using a highly conserved 25 amino acid segment, designated ZNS, at its C terminus. ZNS shares no sequence homology with other known nuclear localization or export signals. Attachment of ZNS to a red fluorescent protein DsRed2 confers the nucleocytoplasmic shuttling ability to that protein. The nuclear localization of DAZAP1 depends on active transcription. In the presence of an RNA polymerase II inhibitor, DAZAP1 is retained in the cytoplasm. DAZAP1 colocalizes with hnRNP A1 and hnRNP C1 in the nucleus and is a component of the heterogeneous nuclear ribonucleoprotein particles. Our results suggest that DAZAP1 plays a key role in mRNA transport during spermatogenesis.
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
authors.forename: Yi-Tzu
authors.initials: YT
authors.lastname: Lin
authors.forename: Pauline H
authors.initials: PH
authors.lastname: Yen
mesh_terms: D016475:3T3 Cells; D021581:Active Transport, Cell Nucleus / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D002522:Chlorocebus aethiops; D017124:Conserved Sequence; D003593:Cytoplasm / Q000378:metabolism*; D003609:Dactinomycin / Q000494:pharmacology; D006367:HeLa Cells; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B / Q000302:isolation & purification / Q000378:metabolism; D034482:Heterogeneous-Nuclear Ribonucleoprotein Group C / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D019913:Nuclear Localization Signals; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D013737:Testis / Q000737:chemistry*; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034482:Heterogeneous-Nuclear Ribonucleoprotein Group C; D019913:Nuclear Localization Signals; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D003609:Dactinomycin