Intracellular trafficking of VP22 in bovine herpesvirus-1 infected cells.
The intracellular trafficking of different VP22-enhanced yellow fluorescent protein (EYFP) fusion proteins expressed by bovine herpesvirus-1 (BHV-1) recombinants was examined by live-cell imaging. Our results demonstrate that (i) the fusion of EYFP to the C terminus of VP22 does not alter the trafficking of the protein in infected cells, (ii) VP22 expressed during BHV-1 infection translocates to the nucleus through three different pathways, namely early mitosis-dependent nuclear translocation, late massive nuclear translocation that follows a prolonged cytoplasmic stage of the protein in non-mitotic cells, and accumulation of a small subset of VP22 in discrete dot-like nuclear domains during its early cytoplasmic stage, (iii) the addition of the SV40 large-T-antigen nuclear localization signal (NLS) to VP22-EYFP abrogates its early cytoplasmic stage, and (iv) the VP22 (131)PRPR(134) NLS is not required for the late massive nuclear translocation of the protein, but this motif is essential for the targeting of VP22 to discrete dot-like nuclear domains during the early cytoplasmic stage. These results show that the amount of VP22 in the nucleus is precisely regulated at different stages of BHV-1 infection and suggest that the early pathways of VP22 nuclear accumulation may be more relevant to the infection process as the late massive nuclear influx starts when most of the viral progeny has already emerged from the cell.
Lobanov
Vladislav A
VA
Vaccine and Infectious Disease Organization, University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK, Canada.
Zheng
C
C
Babiuk
Lorne A
LA
van Drunen Littel-van den Hurk
Sylvia
S
D021581:Active Transport, Cell Nucleus; D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism; D015153:Blotting, Western; D002417:Cattle; D002418:Cattle Diseases / Q000821:virology; D002467:Cell Nucleus / Q000821:virology; D003593:Cytoplasm / Q000821:virology; D004591:Electrophoresis, Polyacrylamide Gel; D006566:Herpesviridae Infections / Q000378:metabolism; D007242:Herpesvirus 1, Bovine / Q000378:metabolism*; D008164:Luminescent Proteins / Q000378:metabolism; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015678:Viral Structural Proteins / Q000378:metabolism*
D001426:Bacterial Proteins; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D015678:Viral Structural Proteins; C054562:yellow fluorescent protein, Bacteria