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Updated: May 14, 2026
06:10
Following Cell-fate in E. coli After Infection by Phage Lambda
Published on: October 14, 2011
Phage Lambda P protein: trans-activation, inhibition phenotypes and their suppression.
Sidney Hayes1, Craig Erker, Monique A Horbay
1Department of Microbiology and Immunology, College of Medicine, University of Saskatchewan, Saskatoon, S7N 5E5, Canada. sidney.hayes@usask.ca
Viruses
|February 8, 2013
Summary
Bacteriophage P protein interferes with bacterial DNA replication by targeting host proteins like DnaB. This study reveals P
Area of Science:
- Molecular Biology
- Virology
- Microbiology
Background:
- Bacteriophage lambda (λ) replication initiation involves interactions between viral proteins (O and P) and Escherichia coli host replication machinery.
- The phage P protein has a high affinity for the E. coli DnaB helicase, a key enzyme in DNA replication.
- P-lethality is a phenomenon where P expression is toxic to host cells, potentially by sequestering DnaB and inhibiting bacterial DNA replication initiation.
Purpose of the Study:
- To investigate the mechanism of P-lethality and its impact on E. coli replication.
- To differentiate the effects of P protein on plasmid replication versus chromosomal replication.
- To identify host factors that confer resistance to P protein's effects.
Main Methods:
- Utilized a conditional expression plasmid for bacteriophage P protein in E. coli.
- Assessed transformation efficiency of ColE1-type plasmids under P protein expression.
- Examined the effect of P protein expression on cell viability, filamentation, and plasmid establishment.
- Investigated the role of specific E. coli dnaB alleles and SOS response mutations (ΔrecA, lexA[Ind-]) in P protein toxicity.
Main Results:
- ColE1 plasmid replication and establishment are highly sensitive to bacteriophage P protein expression, distinct from P-lethality.
- Specific alleles of the dnaB gene confer protection to E. coli cells against P protein expression.
- P protein-dependent cellular filamentation occurs in E. coli cells deficient in SOS induction (ΔrecA or lexA[Ind-]).
Conclusions:
- Bacteriophage P protein interferes with E. coli DNA replication at multiple levels, including plasmid establishment and potentially replication propagation and restart.
- The DnaB protein is a key target for P protein's inhibitory effects on bacterial DNA replication.
- P-lethality and its impact on replication are complex and may involve targets beyond oriC-dependent initiation.
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