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Prophage induction and inactivation by UV light
Journal of Virology
|June 1, 1976
Summary
UV light induces prophage in Haemophilus influenzae when a pyrimidine dimer is stabilized within the prophage genome. DNA repair mechanisms reduce this induction probability by removing dimers.
Area of Science:
- Microbiology
- Molecular Biology
- Bacteriology
Background:
- Bacterial viruses (bacteriophages) can integrate into the host genome.
- UV irradiation is a known inducer of prophage, leading to viral replication.
- DNA repair mechanisms play a crucial role in cellular response to damage.
Purpose of the Study:
- To investigate the role of pyrimidine dimers in prophage induction.
- To understand the mechanism of UV-induced prophage activation in Haemophilus influenzae.
- To explore the influence of host DNA repair systems on prophage inducibility.
Main Methods:
- Analysis of induction curves in UV-irradiated Haemophilus influenzae lysogens.
- Distribution analysis of pyrimidine dimers in repair-deficient lysogens.
- Correlation studies between dimer presence and prophage induction events.
Main Results:
- One pyrimidine dimer per prophage-sized DNA segment is required for preinduction.
- Direct prophage induction correlates with dimer stabilization within the prophage genome.
- Host excision-repair systems decrease the likelihood of dimer stabilization for induction.
Conclusions:
- Pyrimidine dimer formation and stabilization are critical for direct prophage induction.
- Host DNA repair pathways modulate the efficiency of prophage induction.
- The presence of a defective prophage can affect the inducibility of other prophages.