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Following Cell-fate in E. coli After Infection by Phage Lambda
Published on: October 14, 2011
Control of bacteriophage mu lysogenic repression
Caroline Ranquet1, Ariane Toussaint, Hidde de Jong
1Laboratoire du Contrôle de l'Expression Génique, Institut Jean Roget-Faculté de Médecine-Pharmacie, Domaine de la Merci, F-38700 La Tronche, France. cranquet@cea.fr
Journal of Molecular Biology
|September 13, 2005
Summary
The repressor protein Rep accumulates during phage Mu induction, unexpectedly stabilized by ClpX and proteases. This sequestration explains how phage Mu controls the lysis-lysogeny decision.
Area of Science:
- Microbiology
- Molecular Biology
- Bacteriology
Background:
- Phage Mu is a transposable and temperate bacteriophage that infects Escherichia coli.
- The lysis-lysogeny decision in phage Mu is regulated by the repressor protein Rep.
- Understanding Rep's fate is crucial for deciphering phage-host interactions.
Purpose of the Study:
- To investigate the stability and degradation of the Rep protein under conditions inducing phage Mu lysogeny.
- To elucidate the role of cellular proteases in regulating Rep levels.
- To model the mechanisms governing the lysis-lysogeny decision.
Main Methods:
- Western blotting to analyze Rep protein levels in various Escherichia coli mutants.
- Investigating Rep fate under high temperature and stationary phase induction conditions.
- Analyzing degradation kinetics and the impact of clpP and lon gene inactivation.
Main Results:
- Rep accumulates under conditions of complete prophage derepression, dependent on ClpX.
- Rep is a target for both ClpP and Lon protease systems, as inactivation of either stabilizes Rep.
- Derepression correlates with high repressor concentration due to sequestration in a non-active form.
Conclusions:
- Phage Mu induction involves the sequestration of the Rep repressor in a non-active form.
- Cellular proteases, ClpX, ClpP, and Lon, play critical roles in regulating Rep stability and phage induction.
- A quantitative model accurately describes Mu induction dynamics and the convergence of physiological signals on Rep.
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