Control of replication in RNA bacteriophages.

Area of Science:

• Molecular Virology
• Bacteriophage Genetics
• RNA Replication

Background:

• Bacteriophages are viruses that infect bacteria, offering a model system to study fundamental biological processes.
• Understanding viral RNA and protein synthesis is crucial for deciphering viral replication strategies.
• Amber mutants and suppressor strains of *Escherichia coli* allow precise investigation of gene function and protein synthesis.

Purpose of the Study:

• To determine the rates of viral RNA and protein synthesis for wild-type bacteriophages and coat protein mutants.
• To investigate the role of coat protein and replicase in regulating viral RNA synthesis.
• To explore the potential for translational control of viral RNA replication.

Main Methods:

• Infection of amber suppressor and nonsuppressor *Escherichia coli* strains with wild-type and coat protein amber mutant bacteriophages.
• Measurement of viral RNA (plus and minus strands) and protein (replicase) synthesis rates in the presence of rifamycin.
• Analysis of synthesis rates under conditions of partial protein synthesis inhibition.

Main Results:

• Phage replicase and RNA minus-strand synthesis declined concurrently in both wild-type and mutant infections.
• RNA plus-strand synthesis decline lagged behind replicase and minus-strand synthesis.
• Excess replicase in coat protein mutants led to overproduction of minus strands, suggesting replicase's role in minus-strand synthesis and potential self-regulation.

Conclusions:

• Viral replicase and minus-strand RNA synthesis are coupled, potentially regulated at the translational level.
• The coat protein influences replicase accumulation, and excess replicase may inhibit its own synthesis.
• This coupling provides a mechanism for controlling viral RNA replication.