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The rex genes of bacteriophage lambda can inhibit cell function without phage superinfection
1Department of Microbiology, Michigan State University, East Lansing 48824.
Gene
|September 1, 1989
Summary
Bacteriophage lambda Rex proteins, RexA and RexB, cause superinfection exclusion. Overexpressing RexA with limited RexB halts cell growth, protein synthesis, and amino acid transport, suggesting ratio changes drive exclusion.
Area of Science:
- Molecular Biology
- Virology
- Genetics
Background:
- Bacteriophage lambda's rexA and rexB genes are crucial for prophage exclusion of superinfecting phages.
- Understanding the precise mechanisms of phage exclusion is vital in viral genetics and molecular biology.
Purpose of the Study:
- To investigate the phenotypic effects of overexpressing bacteriophage lambda's rexA and rexB genes.
- To elucidate the role of Rex protein ratios in phage exclusion.
Main Methods:
- Cloning rexA and rexB genes into a multicopy plasmid under an inducible tac promoter.
- Overexpression of Rex proteins and observation of cellular phenotypes, including growth, macromolecular synthesis, and transport.
Main Results:
- Overexpression of both rexA and rexB, or rexA alone, showed no significant phenotype.
- Induction of rexA with limiting rexB activity led to immediate growth cessation.
- Macromolecular synthesis and amino acid transport were severely inhibited, with a drop in intracellular ATP levels.
Conclusions:
- The ratio of RexA to RexB proteins is critical for mediating cellular effects.
- Rex protein ratio alterations likely contribute significantly to the exclusion of superinfecting phages, mimicking effects seen during natural superinfection.