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UvsW protein regulates bacteriophage T4 origin-dependent replication by unwinding R-loops
1Department of Microbiology, Duke University Medical Center, Durham, North Carolina 27710, USA.
Molecular and Cellular Biology
|April 3, 2001
Summary
Bacteriophage T4's UvsW protein acts as an RNA-DNA helicase, dissociating RNA from origin R-loops during DNA replication. This function is crucial for regulating replication modes in T4 phage infections.
Area of Science:
- Molecular Biology
- Virology
- Genetics
Background:
- Bacteriophage T4 UvsW protein is vital for phage DNA metabolism, including repair and replication.
- UvsW is implicated in repressing origin-dependent replication and is synthesized late in infection.
- Two T4 origins, ori(uvsY) and ori(34), are thought to initiate replication via an R-loop mechanism.
Purpose of the Study:
- To investigate the role of UvsW protein in bacteriophage T4 DNA replication.
- To determine if UvsW functions as an RNA-DNA helicase involved in R-loop dissociation.
Main Methods:
- In vivo studies using bacteriophage T4 infections and two-dimensional gel electrophoresis.
- In vitro experiments with purified UvsW protein and synthetic origin R-loops.
Main Results:
- Replicative intermediates at ori(uvsY) persisted longer in uvsW mutant infections.
- Early UvsW expression led to the loss of replicative intermediates.
- Purified UvsW efficiently dissociated RNA from synthetic R-loops in vitro.
Conclusions:
- UvsW functions as an RNA-DNA helicase, catalyzing RNA removal from origin R-loops.
- UvsW acts as a molecular switch, transitioning T4 replication from R-loop to D-loop initiation modes.
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