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Updated: Jul 31, 2026
18:10
Isolation of Fidelity Variants of RNA Viruses and Characterization of Virus Mutation Frequency
Published on: June 16, 2011
Function of a 5'-end genomic RNA mutation that evolves during persistent mouse hepatitis virus infection in vitro
1Department of Epidemiology, University of North Carolina at Chapel Hill 27599-7400, USA.
Journal of Virology
|December 1, 1995
Summary
Mouse hepatitis virus (MHV) persistence in cells is linked to a specific mutation in the 5' untranslated region (UTR). This mutation enhances viral replication and cytolytic activity, driving viral evolution during infection.
Area of Science:
- Virology
- Molecular Biology
- Genetics
Background:
- Persistent viral infections can arise from complex host-pathogen interactions.
- Understanding viral evolution during chronic infection is crucial for developing therapeutic strategies.
- Mouse hepatitis virus (MHV) is a model coronavirus for studying viral pathogenesis and persistence.
Purpose of the Study:
- To investigate the evolution of the MHV-A59 genome, particularly the leader RNA and 5' end, during persistent infection in DBT cells.
- To identify specific mutations associated with viral persistence and their functional consequences.
- To elucidate the role of 5' end mutations in viral replication, translation, and cytolytic activity.
Main Methods:
- Establishing persistently infected DBT cell cultures with MHV-A59.
- Performing sequence analysis of viral clones to determine mutation frequency and fixation rates.
- Utilizing in vitro translation assays to assess the impact of mutations on gene expression.
- Isolating and characterizing variant viruses with specific mutations for replication and cytolytic assays.
Main Results:
- High mutation frequencies (1.2 x 10(-3) to 6.7 x 10(-3)) and fixation rates (1.2 x 10(-5) to 7.6 x 10(-5) nt/day) were observed.
- MHV leader RNA remained stable, but a specific A-to-G mutation at nucleotide 77 in the 5' untranslated region (UTR) emerged and accumulated.
- This 5' UTR mutation enhanced translation of the downstream p28 open reading frame (ORF) by approximately 2.5-fold in vitro and 3.5-fold in cells.
- Variant viruses with the 5' UTR mutation exhibited more efficient replication and increased cytolytic activity in DBT cells.
Conclusions:
- Viral persistence in MHV-infected DBT cells is significantly associated with mutations in the 5' UTR.
- The identified 5' UTR mutation enhances viral translation and replication, contributing to viral pathogenesis.
- These findings highlight the importance of 5' UTR evolution in viral persistence and virulence.
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