Assembly intermediates among adenovirus type 5 temperature-sensitive mutants

Area of Science:

• Molecular Biology
• Virology
• Genetics

Background:

• Temperature-sensitive (ts) mutants are crucial tools for studying viral replication and assembly.
• Understanding the kinetics of viral intermediate processing is key to deciphering assembly pathways.

Purpose of the Study:

• To investigate the role of viral assembly intermediates in the replication cycle.
• To characterize the fate of intermediates formed by temperature-sensitive mutants at restrictive temperatures.

Main Methods:

• Utilizing temperature-sensitive mutants (ts5, ts19, 6s58) to study viral assembly.
• Analyzing polypeptide composition of accumulated intermediates.
• Performing temperature shift-down experiments to assess recovery of infectious virus.

Main Results:

• Three ts mutants accumulated viral assembly intermediates with wild-type polypeptide composition, including precursor proteins pVI, pVII, and pVIII.
• Mutants ts5 and ts19 showed evidence of precursor cleavage, indicating assembly into defective virions.
• Rapid recovery of infectious virus in ts19 and ts58 upon shift-down suggested intermediates can be processed, but only a fraction was utilized, with degradation occurring at restrictive temperatures.

Conclusions:

• Viral assembly intermediates accumulate in specific temperature-sensitive mutants.
• These intermediates can be processed into infectious virions, but this pathway is not fully efficient.
• Degradation of intermediates at restrictive temperatures is a significant factor in viral replication dynamics.