Phenotypic characterization of a vaccinia virus temperature-sensitive complementation group affecting a virion...

Area of Science:

• Virology
• Molecular Biology
• Genetics

Background:

• The vaccinia virus is a large, complex DNA virus with a double-stranded genome.
• Understanding vaccinia virus gene function is crucial for developing effective antiviral therapies.
• Gene 18R's role in viral structure and replication has not been fully elucidated.

Purpose of the Study:

• To characterize the vaccinia virus gene 18R product.
• To determine the function of the 18R gene product in viral assembly and maturation.
• To investigate the impact of 18R mutations on vaccinia virus replication.

Main Methods:

• Western blot analysis was used to detect the 18R gene product in purified virions.
• Temperature-sensitive (ts) mutants mapping to gene 18R were generated and analyzed.
• Single-step growth curves and temperature shift experiments were performed with ts mutants.

Main Results:

• Genetic and biochemical evidence confirmed the 18R gene product is a virion protein.
• A 78,000-Da protein encoded by gene 18R was identified in the virus core.
• Two mutants (ts 10 and ts 44) exhibited thermolabile virions, indicating a role in structural integrity.
• Accumulation of maturation precursors and requirement for protein synthesis for recovery were observed in 18R mutants.

Conclusions:

• The vaccinia virus 18R gene encodes a structural virion protein located in the virus core.
• This protein plays a critical role in vaccinia virus virion maturation and infectivity.
• Understanding the function of the 18R protein provides insights into viral assembly and potential therapeutic targets.