Effect of Human Coronavirus OC43 Structural and Accessory Proteins on the Transcriptional Activation of Antiviral...

Area of Science:

• Virology
• Molecular Biology
• Immunology

Background:

• The pathogenesis of human coronavirus OC43 (HCoV-OC43) is not fully understood.
• Investigating viral mechanisms that evade host immune responses is critical for understanding viral diseases.

Purpose of the Study:

• To investigate the role of HCoV-OC43 proteins in antagonizing antiviral transcriptional activation.
• To determine how HCoV-OC43 structural (M, N) and accessory (ns2a, ns5a) proteins impact host antiviral responses.

Main Methods:

• Expression of individual HCoV-OC43 proteins (M, N, ns2a, ns5a) in human embryonic kidney 293 (HEK-293) cells.
• Assessment of transcriptional activation of interferon-stimulated response element (ISRE), IFN-β promoter, and nuclear factor kappa B response element (NF-κB-RE) using luciferase reporter assays.
• Analysis of antiviral gene expression profiles using PCR arrays.

Main Results:

• HCoV-OC43 ns2a, ns5a, M, and N proteins significantly reduced the transcriptional activity of ISRE, IFN-β promoter, and NF-κB-RE.
• Downregulation of antiviral gene expression in type I interferon and NF-κB signaling pathways was observed in the presence of HCoV-OC43 proteins.
• These inhibitory effects were noted after challenging cells with Sendai virus, IFN-α, or tumor necrosis factor-α.

Conclusions:

• Both structural and accessory proteins of HCoV-OC43 can inhibit antiviral response elements.
• HCoV-OC43 proteins effectively block the activation of critical antiviral signaling pathways, contributing to viral pathogenesis.