Ribosome Pausing at Inefficient Codons at the End of the Replicase Coding Region Is Important for Hepatitis C Virus...

Area of Science:

• Virology
• Molecular Biology
• Hepatitis C Research

Background:

• Hepatitis C virus (HCV) infection can lead to chronic liver disease, cirrhosis, and cancer.
• HCV RNA genome is translated into viral proteins, including the NS5B replicase, essential for viral RNA replication.
• NS5B replicase initiates RNA genome replication at the 3' end of the plus strand.

Purpose of the Study:

• To investigate the role of ribosome pausing at the HCV stop codon.
• To understand the impact of codon efficiency on viral RNA replication and protein synthesis.
• To explore the mechanism by which NS5B replicase interacts with the RNA template.

Main Methods:

• Ribosome profiling of cells replicating full-length infectious HCV genomes.
• Analysis of ribosome accumulation patterns at the HCV stop codon.
• Synonymous codon substitution experiments to assess functional consequences.

Main Results:

• Ribosomes accumulate approximately 30 nucleotides upstream of the HCV stop codon.
• Conserved, inefficient Wobble codons cause this ribosome pausing.
• Substituting inefficient codons with efficient ones impairs viral RNA replication but not protein synthesis.

Conclusions:

• Ribosome pausing at the HCV stop codon, mediated by inefficient codons, is essential for viral RNA replication.
• This pausing mechanism may facilitate the NS5B replicase's interaction with its RNA template.
• Codon usage plays a critical role in regulating HCV replication and pathogenesis.