The relationship between mutation frequency and replication strategy in positive-sense single-stranded RNA viruses

Area of Science:

• Virology
• Molecular Biology
• Genetics

Background:

• Positive-sense single-stranded RNA viruses balance transcription, translation, and encapsidation.
• Iterative positive-to-negative-to-positive sense RNA transcription maximizes viral growth rate.
• High mutation rates in RNA viruses increase lethal mutations with replication cycles.

Purpose of the Study:

• To model the impact of mutation rates on viral replication strategies.
• To determine if maximizing viral growth rate is compatible with high mutation rates.
• To explore alternative viral replication strategies under high mutation loads.

Main Methods:

• Mathematical modeling of viral replication dynamics.
• Incorporation of realistic mutation rates into the model.
• Analysis of mutant frequency and viral viability under different replication strategies.

Main Results:

• Maximizing viral growth can lead to an average of 26 mutations per genome, reducing viability to 0.1%.
• High mutation rates shift optimal strategies towards increased negative strand synthesis or 'stamping-machine' replication.
• The model demonstrates a conflict between maximizing growth rate and minimizing lethal mutations.

Conclusions:

• If current viral mutation rate estimates are accurate, RNA virus replication may not be optimized for maximum growth rate.
• Alternatively, mutation frequencies could be higher, and viable virus yields much lower than anticipated.
• Mechanistic models and deep-sequencing are crucial for refining viral mutation rate estimates.