title: Murine leukemia virus uses TREX components for efficient nuclear export of unspliced viral transcripts.
abstract: Previously we reported that nuclear export of both unspliced and spliced murine leukemia virus (MLV) transcripts depends on the nuclear export factor (NXF1) pathway. Although the mRNA export complex TREX, which contains Aly/REF, UAP56, and the THO complex, is involved in the NXF1-mediated nuclear export of cellular mRNAs, its contribution to the export of MLV mRNA transcripts remains poorly understood. Here, we studied the involvement of TREX components in the export of MLV transcripts. Depletion of UAP56, but not Aly/REF, reduced the level of both unspliced and spliced viral transcripts in the cytoplasm. Interestingly, depletion of THO components, including THOC5 and THOC7, affected only unspliced viral transcripts in the cytoplasm. Moreover, the RNA immunoprecipitation assay showed that only the unspliced viral transcript interacted with THOC5. These results imply that MLV requires UAP56, THOC5 and THOC7, in addition to NXF1, for nuclear export of viral transcripts. Given that naturally intronless mRNAs, but not bulk mRNAs, require THOC5 for nuclear export, it is plausible that THOC5 plays a key role in the export of unspliced MLV transcripts.
authors.affiliation: Department of Molecular Medicine, Mayo Clinic, Rochester, MN 55905 USA. sakuma.toshie@mayo.edu.
authors.forename: Toshie
authors.initials: T
authors.lastname: Sakuma
authors.affiliation: Department of Molecular Medicine, Mayo Clinic, Rochester, MN 55905 USA. tonne.jason@mayo.edu.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Tonne
authors.affiliation: Department of Molecular Medicine, Mayo Clinic, Rochester, MN 55905 USA. ikeda.yasuhiro@mayo.edu.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ikeda
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D053487:DEAD-box RNA Helicases / Q000378:metabolism*; D009052:Leukemia Virus, Murine / Q000502:physiology*; D009687:Nuclear Proteins / Q000378:metabolism*; D029543:Nucleocytoplasmic Transport Proteins / Q000378:metabolism; D012367:RNA, Viral / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D014779:Virus Replication
chemical_list: C569386:NXF1 protein, mouse; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; D012367:RNA, Viral; D016601:RNA-Binding Proteins; C559981:THOC5 protein, mouse; C000592392:THOC7 protein, mouse; C518885:Ddx39b protein, mouse; D053487:DEAD-box RNA Helicases