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Interaction of P2 bacteriophage with the dnaB gene of Escherichia coli
Abstract:
The dnaB gene product of Escherischia coli is required for multiplication of temperate phage P2. At 37 C in dnaB-ts mutnats, P2 will not plaque and gives a very small burst of progeny. P2 mutants have been isolated which can grow well enough to plaque under these conditions. This type of phage mutant is cis dominant, and one such mutant (P2rlb1) has been mapped near the left end of the early gene B and to the right of the cox4 (excision) mutation. The rlb1 mutation does not lie at the replication origin, but may affect transcription in the early region, which includes the replication origin. It may also represent a site on the P2 DNA which interacts with the dnaB gene product.
Insights
Researchers identified specific mutations in the P2 phage that allow it to replicate even when the host
Area of Science:
- Microbiology
- Molecular Biology
- Virology
Background:
- The dnaB gene product of Escherichia coli is essential for the replication of temperate phage P2.
- Temperature-sensitive dnaB mutants of E. coli prevent P2 phage multiplication at restrictive temperatures.
Purpose of the Study:
- To isolate and characterize P2 phage mutants capable of replicating in dnaB-ts mutant E. coli at restrictive temperatures.
- To understand the interaction between phage P2 and the host dnaB gene product.
Main Methods:
- Isolation of P2 phage mutants resistant to dnaB-ts host conditions.
- Genetic mapping of the isolated P2 mutants.
- Analysis of P2 mutant replication and plaque formation in dnaB-ts E. coli.
Main Results:
- P2 phage mutants were isolated that can plaque on dnaB-ts E. coli at 37°C.
- One mutant, P2rlb1, was mapped near the early gene B and to the right of the cox4 mutation.
- The rlb1 mutation is cis-dominant and may affect early region transcription or interaction with the dnaB gene product.
Conclusions:
- Mutations in P2 phage can overcome dependence on the host dnaB gene product for replication.
- The P2 rlb1 mutation provides insights into phage-host interactions and potential regulatory mechanisms of phage DNA replication.
- The rlb1 mutation may identify a specific site on P2 DNA interacting with the essential dnaB replication factor.