A novel nucleocytoplasmic shuttling sequence of DAZAP1, a testis-abundant RNA-binding protein

• Published in: RNA (Cambridge) 2006-08, Vol.12 (8), p.1486-1493
• Main Authors: Lin, Yi-Tzu, Yen, Pauline H
• Format: Article
• Language: English
• Subjects: 3T3 Cells; Active Transport, Cell Nucleus - physiology; Amino Acid Sequence; Animals; Cell Line; Cell Nucleus - metabolism; Cercopithecus aethiops; Conserved Sequence; COS Cells; Cytoplasm - metabolism; Dactinomycin - pharmacology; HeLa Cells; Heterogeneous Nuclear Ribonucleoprotein A1; Heterogeneous-Nuclear Ribonucleoprotein Group A-B - isolation & purification; Heterogeneous-Nuclear Ribonucleoprotein Group A-B - metabolism; Heterogeneous-Nuclear Ribonucleoprotein Group C - isolation & purification; Heterogeneous-Nuclear Ribonucleoprotein Group C - metabolism; Humans; Male; Mice; Molecular Sequence Data; Mutagenesis, Site-Directed; Mutation; Nuclear Localization Signals; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - metabolism; RNA-Binding Proteins - chemistry; RNA-Binding Proteins - genetics; RNA-Binding Proteins - metabolism; Testis - chemistry; Transcription, Genetic - drug effects
• ISSN: 1355-8382; 1469-9001
• DOI: 10.1261/rna.42206

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.