Related Experiment Video
Updated: Apr 28, 2026
Isolation of Fidelity Variants of RNA Viruses and Characterization of Virus Mutation Frequency
Published on: June 16, 2011
Foot-and-mouth disease virus low-fidelity polymerase mutants are attenuated
Xiaochun Xie1, Haiwei Wang, Jianxiong Zeng
1Division of Livestock Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 427 Maduan Street, Harbin, 150001, P. R. China.
Abstract:
Previous studies have shown that RNA viruses can be attenuated by either increased or decreased viral polymerase replication fidelity. Although foot-and-mouth disease virus (FMDV) high-fidelity RNA-dependent RNA polymerase (RdRp) variants with an attenuated phenotype have been isolated using mutagens, no FMDV mutant with a low-fidelity polymerase has been documented to date. Here, we describe the generation of several FMDV RdRp mutants using site-directed mutagenesis via a reverse genetic system. Mutation frequency assays confirmed that five rescued FMDV RdRp mutant populations had lower replication fidelity than the wild-type virus population, which allowed us to assess the effects of the change in replication fidelity on the virus phenotype. These low-fidelity FMDV RdRp mutants showed increased sensitivity to ribavirin or 5-fluorouracil (5-FU) treatment without a loss of growth capacity in cell cultures. In addition, decreased fitness and attenuated virulence were observed for the RdRp mutants with lower fidelity. Importantly, based on a quantitative analysis for fidelity and virulence, we concluded that lower replication fidelity is associated with a more attenuated virus phenotype. These results further contribute to our understanding of the replication fidelity of polymerases of RNA viruses and its relationship to virulence attenuation.
Insights
Researchers created low-fidelity foot-and-mouth disease virus (FMDV) RNA-dependent RNA polymerase (RdRp) mutants. These mutants showed reduced virulence and increased sensitivity to antiviral drugs, linking low fidelity to virus attenuation.
Area of Science:
- Virology
- Molecular Biology
- Genetics
Background:
- Viral replication fidelity influences RNA virus attenuation.
- High-fidelity foot-and-mouth disease virus (FMDV) variants are known, but low-fidelity mutants are undocumented.
Purpose of the Study:
- To generate and characterize FMDV RNA-dependent RNA polymerase (RdRp) mutants with reduced replication fidelity.
- To investigate the relationship between FMDV replication fidelity and viral phenotype, including drug sensitivity, fitness, and virulence.
Main Methods:
- Site-directed mutagenesis was used to create FMDV RdRp mutants within a reverse genetics system.
- Mutation frequency assays were employed to confirm reduced replication fidelity in rescued mutant populations.
- Phenotypic analyses assessed drug sensitivity (ribavirin, 5-FU), growth capacity, fitness, and virulence.
Main Results:
- Five FMDV RdRp mutant populations exhibited significantly lower replication fidelity compared to wild-type.
- Low-fidelity mutants displayed increased sensitivity to ribavirin and 5-FU without compromising growth in cell culture.
- Mutants with decreased replication fidelity showed reduced viral fitness and attenuated virulence.
Conclusions:
- Lower replication fidelity in FMDV RdRp is quantitatively associated with a more attenuated virus phenotype.
- These findings enhance understanding of the role of RNA virus polymerase fidelity in virulence attenuation.
- Low-fidelity FMDV mutants represent potential candidates for further study in antiviral strategies.
Related Concept Videos
01:18Mutations in Microorganisms
00:36Viral Mutations