A small region of the dengue virus-encoded RNA-dependent RNA polymerase, NS5, confers interaction with both the nuclear transport receptor importin-beta and the viral helicase, NS3.
The dengue virus RNA-dependent RNA polymerase, NS5, and the protease/helicase, NS3, are multidomain proteins that have been shown to interact both in vivo and in vitro. A hyperphosphorylated form of NS5 that does not interact with NS3 has been detected in the nuclei of virus-infected cells, presumably as the result of the action of a functional nuclear localization sequence within the interdomain region of NS5 (residues 369-405). In this study, it is shown by using the yeast two-hybrid system that the C-terminal region of NS3 (residues 303-618) interacts with the N-terminal region of NS5 (residues 320-368). Further, it is shown that this same region of NS5 is also recognized by the cellular nuclear import receptor importin-beta. The interaction between NS5 and importin-beta and competition by NS3 with the latter for the same binding site on NS5 were confirmed by pull-down assays. The direct interaction of importin-beta with NS5 has implications for the mechanism by which this normally cytoplasmic protein may be targetted to the nucleus.
Department of Biochemistry and Molecular Biology, James Cook University, Townsville, Queensland 4811, Australia1.
Magnus
M
Johansson
Department of Biochemistry and Molecular Biology, James Cook University, Townsville, Queensland 4811, Australia1.
Andrew J
AJ
Brooks
Nuclear Signalling Laboratory, Division of Biochemistry and Molecular Biology, John Curtin School of Medical Research, Canberra, Australia2.
David A
DA
Jans
Department of Biochemistry and Molecular Biology, James Cook University, Townsville, Queensland 4811, Australia1.
Subhash G
SG
Vasudevan
D000330:Aedes; D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D003716:Dengue Virus / Q000201:enzymology*; D028884:Karyopherins; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D020365:RNA Helicases / Q000378:metabolism*; D012697:Serine Endopeptidases; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000378:metabolism*; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
D028884:Karyopherins; D009687:Nuclear Proteins; D020365:RNA Helicases; D012697:Serine Endopeptidases; D017361:Viral Nonstructural Proteins; C060028:NS3 protein, flavivirus; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C096041:NS5 protein, flavivirus