A 14,000-Mr envelope protein of vaccinia virus is involved in cell fusion and forms covalently linked trimers
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Abstract:
A monoclonal antibody, MAbC3, that reacts with a 14,000-molecular-weight envelope protein (14K protein) of vaccinia virus completely inhibited virus-induced cell fusion during infection. Immunoblot and immunofluorescence studies revealed that the 14K protein was synthesized at about 6 to 7 h postinfection and transported from the cytoplasm to the cell surface. Synthesis and transport of the 14K protein during infection occurred in the presence of rifampin, an inhibitor of virus maturation. One- and two-dimensional gel electrophoretic analyses demonstrated that the 14K protein forms largely trimers (42K) that are covalently linked by disulfide bonds. The facts that MAbC3 prevents virus uncoating and blocks virus-induced cell fusion but does not prevent virus attachment to cells and the 14K envelope protein forms trimers all suggest that this protein plays major role in virus penetration.
Insights
A specific antibody targeting the vaccinia virus 14K envelope protein inhibits cell fusion and virus uncoating. This 14K protein, forming trimers, is crucial for vaccinia virus penetration into host cells.
Area of Science:
- Virology
- Immunology
- Molecular Biology
Background:
- Vaccinia virus infection involves complex interactions between viral proteins and host cells.
- Understanding viral envelope proteins is key to developing antiviral strategies.
Purpose of the Study:
- To investigate the role of a specific vaccinia virus envelope protein (14K protein) in viral infection.
- To characterize the function of the 14K protein in virus-induced cell fusion and penetration.
Main Methods:
- Monoclonal antibody (MAbC3) production and characterization.
- Immunoblot and immunofluorescence assays to detect protein synthesis and localization.
- Gel electrophoresis to analyze protein structure (trimers).
- Infection assays to assess cell fusion and virus uncoating inhibition.
Main Results:
- MAbC3 specifically targets the vaccinia virus 14K envelope protein.
- The 14K protein is synthesized and transported to the cell surface starting 6-7 hours post-infection.
- The 14K protein exists primarily as disulfide-linked trimers (42K).
- MAbC3 inhibited virus-induced cell fusion and prevented virus uncoating, but not attachment.
Conclusions:
- The vaccinia virus 14K envelope protein plays a significant role in virus penetration.
- The trimeric structure of the 14K protein is important for its function.
- Targeting the 14K protein with antibodies offers a potential antiviral approach.