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.
Johansson
Magnus
M
Department of Biochemistry and Molecular Biology, James Cook University, Townsville, Queensland 4811, Australia1.
Brooks
Andrew J
AJ
Department of Biochemistry and Molecular Biology, James Cook University, Townsville, Queensland 4811, Australia1.
Jans
David A
DA
Nuclear Signalling Laboratory, Division of Biochemistry and Molecular Biology, John Curtin School of Medical Research, Canberra, Australia2.
Vasudevan
Subhash G
SG
Department of Biochemistry and Molecular Biology, James Cook University, Townsville, Queensland 4811, Australia1.
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