Retracted: Nucleocapsid protein of SARS-CoV activates the expression of cyclooxygenase-2 by binding directly to regulatory elements for nuclear factor-kappa B and CCAAT/enhancer binding protein.
SARS-associated coronavirus (SARS-CoV) causes inflammation and damage to the lungs resulting in severe acute respiratory syndrome. To evaluate the molecular mechanisms behind this event, we investigated the roles of SARS-CoV proteins in regulation of the proinflammatory factor, cyclooxygenase-2 (COX-2). Individual viral proteins were tested for their abilities to regulate COX-2 gene expression. Results showed that the COX-2 promoter was activated by the nucleocapsid (N) protein in a concentration-dependent manner. Western blot analysis indicated that N protein was sufficient to stimulate the production of COX-2 protein in mammalian cells. COX-2 promoter mutations suggested that activation of COX-2 transcription depended on two regulatory elements, a nuclear factor-kappa B (NF-kappaB) binding site, and a CCAAT/enhancer binding protein (C/EBP) binding site. Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) demonstrated that SARS-CoV N protein bound directly to these regulatory sequences. Protein mutation analysis revealed that a Lys-rich motif of N protein acted as a nuclear localization signal and was essential for the activation of COX-2. In addition, a Leu-rich motif was found to be required for the N protein function. A sequence of 68 residuals was identified as a potential DNA-binding domain essential for activating COX-2 expression. We propose that SARS-CoV N protein causes inflammation of the lungs by activating COX-2 gene expression by binding directly to the promoter resulting in inflammation through multiple COX-2 signaling cascades.
The State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, PR China.
Xiaohong
X
Yan
Qian
Q
Hao
Yongxin
Y
Mu
Khalid Amine
KA
Timani
Linbai
L
Ye
Ying
Y
Zhu
Jianguo
J
Wu
D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000378:metabolism*; D002460:Cell Line; D047369:Chromatin Immunoprecipitation; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D016297:Mutagenesis, Site-Directed / Q000379:methods; D009154:Mutation; D016328:NF-kappa B / Q000378:metabolism*; D019590:Nucleocapsid Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D045473:Severe acute respiratory syndrome-related coronavirus / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
D022782:CCAAT-Enhancer-Binding Protein-beta; D016328:NF-kappa B; D019590:Nucleocapsid Proteins; D051546:Cyclooxygenase 2