Gene regulatory function and cellular partners of SARS-associated coronavirus nucleocapsid protein
DY Jin1, BJ Zheng2, YP Ching3
1 Department of Biochemistry, The University of Hong Kong
2 Department of Microbiology, The University of Hong Kong
3 Department of Anatomy, The University of Hong Kong
1. SARS coronavirus (SARS-CoV) nucleocapsid (N) protein expressed in cultured human cells was predominantly found in the cytoplasm and was competent in repressing the transcriptional activity driven by interferon-stimulated response elements. Expression of N protein did not influence the transcription from FGL2 promoter. N protein did not modulate the expression of FGL2 mRNA or protein in transfected or SARS-CoV-infected cells.
2. SARS-CoV N and M proteins inhibit gene transcription of type I interferons through different mechanisms. M protein potently antagonises the activation of interferon-stimulated response element-dependent transcription by RIG-I, MDA5, TBK1, IKKε, and VISA, whereas N protein has no influence on these stimuli. The expression of M protein prevents the formation of TRAF3-TANK-TBK1/IKKε complex.