TY - JOUR
T1 - The interdomain region of dengue NS5 protein that binds to the viral helicase NS3 contains independently functional importin β1 and importin α/β-recognized nuclear localization signals
AU - Brooks, Andrew J.
AU - Johansson, Magnus
AU - John, Anna V.
AU - Xu, Yibin
AU - Jans, David A.
AU - Vasudevan, Subhash G.
PY - 2002/9/27
Y1 - 2002/9/27
N2 - Dengue virus NS5 protein is a multifunctional RNA-dependent RNA polymerase that is essential for virus replication. We have shown previously that the 37-amino acid interdomain spacer sequence (residues 369X 2KKX 14KKKX 11 RKX 3 405) of Dengue2 NS5 contains a functional nuclear localization signal (NLS). In this study, β-galactosidase fusion proteins carrying point mutations of the positively charged residues or truncations of the interdomain linker region (residues 369-389 or residues 386-405) were analyzed for nuclear import and importin binding activities to show that the N-terminal part of the linker region (residues 369-389, a/bNLS) is critical for nuclear localization and is recognized with high affinity by the conventional NLS-binding importin α/β heterodimeric nuclear import receptor. We also show that the importin β-binding site (residues 320-368, bNLS) adjacent to the a/bNLS, previously identified by yeast two-hybrid analysis, is functional as an NLS, recognized with high affinity by importin β, and able to target β-galactosidase to the nucleus. Intriguingly, the bNLS is highly conserved among Dengue and related flaviviruses, implying a general role for the region and importin β in the infectious cycle.
AB - Dengue virus NS5 protein is a multifunctional RNA-dependent RNA polymerase that is essential for virus replication. We have shown previously that the 37-amino acid interdomain spacer sequence (residues 369X 2KKX 14KKKX 11 RKX 3 405) of Dengue2 NS5 contains a functional nuclear localization signal (NLS). In this study, β-galactosidase fusion proteins carrying point mutations of the positively charged residues or truncations of the interdomain linker region (residues 369-389 or residues 386-405) were analyzed for nuclear import and importin binding activities to show that the N-terminal part of the linker region (residues 369-389, a/bNLS) is critical for nuclear localization and is recognized with high affinity by the conventional NLS-binding importin α/β heterodimeric nuclear import receptor. We also show that the importin β-binding site (residues 320-368, bNLS) adjacent to the a/bNLS, previously identified by yeast two-hybrid analysis, is functional as an NLS, recognized with high affinity by importin β, and able to target β-galactosidase to the nucleus. Intriguingly, the bNLS is highly conserved among Dengue and related flaviviruses, implying a general role for the region and importin β in the infectious cycle.
UR - http://www.scopus.com/inward/record.url?scp=0037184036&partnerID=8YFLogxK
U2 - 10.1074/jbc.M204977200
DO - 10.1074/jbc.M204977200
M3 - Article
SN - 0021-9258
VL - 277
SP - 36399
EP - 36407
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 39
ER -