Abstract
Varicella-zoster virus open reading frame 10 (ORF10), a tegument protein present in the virion, is a member of the alphaherpesvirus UL48 gene family that shares considerable amino acid sequence homology with the UL48 prototype, herpes simplex virus type 1 VP16. VP16 serves multiple functions, including transcriptional activation of viral immediate-early genes. Furthermore, VP16 has been shown to be involved in some aspects of virus assembly and/or maturation. However, little is known concerning the function of ORF10. Here, we found that transient expression of ORF10 fused to enhanced yellow fluorescent protein (EYFP) in COS-7 cells showed the predominantly nuclear localization in the absence of other viral proteins. By constructing a series of ORF10 variants fused to EYFP, a bona fide bipartite nuclear localization signal of ORF10 was, for the first time, determined and mapped to amino acids (aa) 302-347. Additionally, the nuclear export signal (NES) was identified and found to be in a leucine-rich region at aa 226-236. Finally, ORF10 was demonstrated to be targeted to the cytoplasm through the functional NES by chromosomal region maintenance 1-dependent pathway, and to the nucleus via Ran and importin β1-dependent pathway that does not require importin α5.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism
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COS Cells
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Cell Line
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Cell Nucleus / metabolism*
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Chlorocebus aethiops
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Exportin 1 Protein
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Herpesvirus 3, Human / genetics
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Herpesvirus 3, Human / metabolism*
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Humans
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Karyopherins / genetics
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Karyopherins / metabolism
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Luminescent Proteins / genetics
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Luminescent Proteins / metabolism
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Microscopy, Fluorescence
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Molecular Sequence Data
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Nuclear Export Signals / genetics*
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Nuclear Localization Signals / chemistry
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Nuclear Localization Signals / genetics*
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Protein Transport
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Receptors, Cytoplasmic and Nuclear / genetics
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Receptors, Cytoplasmic and Nuclear / metabolism
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Trans-Activators / chemistry
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Trans-Activators / genetics
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Trans-Activators / metabolism*
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Viral Structural Proteins / genetics
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Viral Structural Proteins / metabolism*
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beta Karyopherins / genetics
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beta Karyopherins / metabolism
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ran GTP-Binding Protein / genetics
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ran GTP-Binding Protein / metabolism
Substances
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Bacterial Proteins
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Karyopherins
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Luminescent Proteins
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Nuclear Export Signals
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Nuclear Localization Signals
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ORF 10 protein, varicella-zoster virus
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Receptors, Cytoplasmic and Nuclear
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Recombinant Fusion Proteins
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Trans-Activators
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Viral Structural Proteins
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beta Karyopherins
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yellow fluorescent protein, Bacteria
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ran GTP-Binding Protein