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Genetic control of mouse leukemia virus replication
Abstract:
The Fv-1 gene of the mouse is a cellular gene, which prevents the replication of murine leukemia viruses. We investigated its intracellular site of action and found that the Fv-1 gene product blocks the appearance of virus-specific RNA in nonpermissive cells, which suggested a transcriptional or a preintegration block. Experiments performed to distinguish between these two possibilities revealed that the Fv-I gene restriction prevents integration of the reverse transcribed proviral DNA into the cell genome. However, we also found that the levels of unintegrated proviral DNA were not significantly affected by the Fv-1 gene restriction soon after infection. These data show that the Fv-1 gene product inhibits a step of the virus life cycle after the synthesis of proviral DNA but before its integration.
Insights
The mouse Fv-1 gene blocks murine leukemia virus replication by preventing proviral DNA integration into the host genome. This restriction occurs after viral DNA synthesis but before its insertion, impacting the virus life cycle.
Area of Science:
- Virology
- Genetics
- Molecular Biology
Background:
- The Fv-1 gene in mice confers resistance to murine leukemia viruses (MLVs).
- Understanding the Fv-1 gene's mechanism is crucial for controlling retroviral infections.
Purpose of the Study:
- To determine the intracellular site of action for the mouse Fv-1 gene.
- To elucidate the specific step in the MLV replication cycle inhibited by Fv-1.
Main Methods:
- Investigated the effect of Fv-1 restriction on virus-specific RNA appearance in nonpermissive cells.
- Conducted experiments to differentiate between transcriptional and preintegration blocks.
- Assessed the levels of unintegrated proviral DNA post-infection.
Main Results:
- Fv-1 restriction prevents the integration of reverse-transcribed proviral DNA into the host cell genome.
- The Fv-1 gene product inhibits a post-DNA synthesis, pre-integration step in the MLV life cycle.
- Levels of unintegrated proviral DNA were not significantly affected by Fv-1 restriction shortly after infection.
Conclusions:
- The Fv-1 gene product acts as a restriction factor targeting the integration step of MLV replication.
- This finding clarifies the mechanism by which Fv-1 confers resistance to MLVs.