Intracellular localization and determination of a nuclear localization signal of the core protein of dengue virus.
In dengue virus (DEN) particles, the core protein is a structural protein of the nucleocapsid. The core protein is known to be present in the nucleus of DEN-infected cells but there have been conflicting reports as to whether it is also present in the nucleolus. To clarify this, the intracellular location of the core protein was examined using a monoclonal antibody, 15B11, which was produced in this study. Immunofluorescence staining with this antibody demonstrated that the core protein first appeared in the cytoplasm and then in the nuclei and nucleoli of infected cells. Nuclear localization of the core protein was determined to be independent of other DEN proteins, since recombinant core proteins still entered the nuclei and nucleoli of cells transfected with only the core protein gene. Three putative nuclear localization signal motifs have been predicted to be present on the core protein. Deletion of the first one (KKAR), located at aa 6-9, and mutation of the second one (KKSK), located at aa 73-76, did not eliminate the nuclear localization property of the core protein. The third motif with a bipartite structure, RKeigrmlnilnRRRR, located at aa 85-100, was determined to be responsible for the nuclear localization of the core protein, since the core protein without this motif was located exclusively in the cytoplasm of DEN-infected cells and that this motif mediated nuclear localization of a normally cytoplasmic protein.
Wang
Shao-Hung
SH
Department of Microbiology and Institute of Microbiology and Immunology, National Yang-Ming University, 155 Li-Nong Street Sec. 2, Shih-Pai, Taipei 112, Taiwan, Republic of China1.
Syu
Wan-Jr
WJ
Department of Microbiology and Institute of Microbiology and Immunology, National Yang-Ming University, 155 Li-Nong Street Sec. 2, Shih-Pai, Taipei 112, Taiwan, Republic of China1.
Huang
Kao-Jean
KJ
Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China2.
Lei
Huan-Yao
HY
Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China2.
Yao
Chen-Wen
CW
Department of Pathology, Tri-service General Hospital, Taipei, Taiwan, Republic of China3.
King
Chwan-Chuen
CC
Institute of Epidemiology, College of Public Health, National Taiwan University, Taipei, Taiwan, Republic of China4.
Hu
Shiau-Ting
ST
Department of Microbiology and Institute of Microbiology and Immunology, National Yang-Ming University, 155 Li-Nong Street Sec. 2, Shih-Pai, Taipei 112, Taiwan, Republic of China1.
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D002460:Cell Line; D002466:Cell Nucleolus / Q000378:metabolism*; D006224:Cricetinae; D003716:Dengue Virus / Q000235:genetics / Q000472:pathogenicity*; D006801:Humans; D008969:Molecular Sequence Data; D019913:Nuclear Localization Signals / Q000737:chemistry*; D014758:Viral Core Proteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D019913:Nuclear Localization Signals; D014758:Viral Core Proteins