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Host range mutants of human rhinovirus in which nonstructural proteins are altered
Abstract:
Human rhinovirus type 2 did not replicate in nonpermissive mouse cells; the restriction was not in adsorption but in the early events of virus replication. Mutants which had been adapted to grow in mouse cells had the following characteristics: (i) no change in the structural protein, (ii) a larger nonstructural protein and its precursor protein, and (iii) an altered viral RNA synthesis. The altered nonstructural proteins correlated with a change in host range of the virus and may be involved in viral RNA synthesis.
Insights
Human rhinovirus type 2 cannot replicate in mouse cells due to early replication block. Adapted viruses show larger nonstructural proteins and altered viral RNA synthesis, suggesting these factors influence host range.
Area of Science:
- Virology
- Molecular Biology
- Host-Pathogen Interactions
Background:
- Human rhinovirus type 2 (HRV2) is a common human pathogen.
- Rodent cells are typically nonpermissive to HRV2 replication.
- Understanding viral replication restrictions is crucial for antiviral development.
Purpose of the Study:
- To investigate the replication restriction of HRV2 in mouse cells.
- To identify viral factors responsible for host range adaptation.
- To elucidate the mechanisms underlying altered viral RNA synthesis.
Main Methods:
- Infection of nonpermissive mouse cells with HRV2.
- Characterization of HRV2 mutants adapted to grow in mouse cells.
- Analysis of viral structural and nonstructural proteins.
- Assessment of viral RNA synthesis.
Main Results:
- HRV2 replication was restricted at early stages, not during adsorption, in mouse cells.
- Adapted HRV2 mutants exhibited no changes in structural proteins.
- Mutants displayed larger nonstructural proteins and their precursors.
- Altered viral RNA synthesis was observed in adapted mutants.
- Changes in nonstructural proteins correlated with expanded host range.
Conclusions:
- The restriction of HRV2 replication in mouse cells occurs at an early post-entry step.
- Nonstructural viral proteins, not structural ones, are key determinants of HRV2 host range.
- Altered nonstructural proteins likely play a role in overcoming replication barriers and modulating viral RNA synthesis.