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Cytosine arabinoside- and interferon-mediated control of polyoma and SV40 genome expression
Abstract:
By metabolic DNA inhibitors such as araC, viral as well as host DNA replication is suppressed in polyoma- and SV40-infected cells. The interruption of the current viral DNA replication has no effect on the current transcription of the late viral genes. The persistence of the late transcription indicates that the onset, but not the persistence, of the viral DNA replication is a prerequisite for the persistence of the late polyoma and SV40 genome transcription. Pretreatment of monkey kidney cells with poly(I):-poly(C) nearly completely inhibits the SV40 T antigen formation; the early SV40 RNA formation is suppressed far less. This type of SV40 genome control favors the concept of a primary action of poly(I):poly(C)-mediated interference on SV40 translation.
Insights
Viral DNA replication inhibitors like araC suppress host and viral DNA replication. Late viral gene transcription persists even when DNA replication is interrupted, indicating onset, not duration, of replication is key for sustained transcription.
Area of Science:
- Molecular Biology
- Virology
- Biochemistry
Background:
- Viral DNA replication is crucial for the life cycle of many viruses, including polyoma and SV40.
- Understanding the regulation of viral gene expression and replication is key to developing antiviral strategies.
Purpose of the Study:
- To investigate the relationship between viral DNA replication and the transcription of late viral genes in polyoma and SV40 infected cells.
- To explore the effect of poly(I):poly(C) on SV40 T antigen formation and early RNA synthesis.
Main Methods:
- Treatment of infected cells with metabolic DNA inhibitors (e.g., araC).
- Analysis of viral DNA replication and gene transcription.
- Pretreatment of cells with poly(I):poly(C) followed by assessment of SV40 T antigen and early RNA formation.
Main Results:
- Inhibition of viral and host DNA replication by araC did not affect ongoing late viral gene transcription.
- The onset, but not the continuous presence, of viral DNA replication is necessary for sustained late gene transcription.
- Poly(I):poly(C) pretreatment significantly inhibited SV40 T antigen formation while only moderately suppressing early SV40 RNA.
Conclusions:
- Viral DNA replication onset is a prerequisite for persistent late viral gene transcription.
- Poly(I):poly(C) appears to primarily interfere with SV40 translation, affecting T antigen formation more than early RNA synthesis.