NS3 protein of Hepatitis C virus associates with the tumour suppressor p53 and inhibits its function in an NS3 sequence-dependent manner.
The N-terminal 198 residues of NS3 (NS3-N) of Hepatitis C virus (HCV) subtype 1b obtained from 29 patients, as well as full-length NS3 (NS3-Full), were analysed for their subcellular localization, interaction with the tumour suppressor p53 and serine protease activity in the presence and absence of the viral cofactor NS4A. Based on the subcellular-localization patterns in the absence of NS4A, NS3-N sequences were classified into three groups, with each group exhibiting either dot-like, diffuse or a mixed type of localization. Chimeric NS3-Full sequences, each consisting of an individual NS3-N and a shared C-terminal sequence, showed the same localization patterns as those of the respective NS3-N. Site-directed mutagenesis experiments revealed that a single or a few amino acid substitutions at a particular position(s) of NS3-N altered the localization pattern. Interestingly, NS3 of the dot-like type, either NS3-N or NS3-Full, interacted with p53 more strongly than that of the diffuse type, in both the presence and the absence of NS4A. Moreover, NS3-N of the dot-like type suppressed trans-activating activity of p53 more strongly than that of the diffuse type. Serine protease activity did not differ significantly between the two types of NS3. In HCV RNA replicon-harbouring cells, physical interaction between NS3 and p53 was observed consistently and p53-mediated transcriptional activation was suppressed significantly compared with HCV RNA-negative control cells. Our results collectively suggest the possibility that NS3 plays an important role in the hepatocarcinogenesis of HCV by interacting differentially with p53 in an NS3 sequence-dependent manner.
Deng
Lin
L
Division of Microbiology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
Nagano-Fujii
Motoko
M
Division of Microbiology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
Tanaka
Motofumi
M
Division of Gastroenterological Surgery, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.|Division of Microbiology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
Nomura-Takigawa
Yuki
Y
Division of Microbiology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
Ikeda
Masanori
M
Department of Molecular Biology, Okayama University Graduate School of Medicine and Dentistry, Okayama 700-8558, Japan.
Kato
Nobuyuki
N
Department of Molecular Biology, Okayama University Graduate School of Medicine and Dentistry, Okayama 700-8558, Japan.
Sada
Kiyonao
K
Division of Microbiology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
Hotta
Hak
H
Division of Microbiology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
D000595:Amino Acid Sequence; D045744:Cell Line, Tumor; D006367:HeLa Cells; D016174:Hepacivirus / Q000145:classification / Q000235:genetics / Q000472:pathogenicity*; D006526:Hepatitis C / Q000473:pathology / Q000821:virology; D006801:Humans; D008969:Molecular Sequence Data; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
D016159:Tumor Suppressor Protein p53; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases