How long can bacteriophage λ change its mind?

Area of Science:

• Microbiology
• Molecular Biology
• Virology

Background:

• Temperate bacteriophages, like bacteriophage lambda (λ), must choose between lysis and lysogeny upon infecting a host.
• A critical regulatory period exists post-decision, allowing a switch from lysogeny to lysis.

Purpose of the Study:

• To investigate the role of the late lytic regulatory protein Q in bacteriophage λ's decision-making process.
• To determine if Q expression triggers DNA replication or if pre-existing DNA is utilized for lysis.

Main Methods:

• Experimental analysis of bacteriophage λ infection dynamics.
• Monitoring of regulatory protein Q accumulation and its effect on host cell fate.
• Assessing the timing of DNA replication relative to Q expression and decision switching.

Main Results:

• Bacteriophage λ can revert from a lysogeny decision to lytic development.
• The accumulation of regulatory protein Q triggers this switch.
• Q expression does not induce bacteriophage λ DNA replication, suggesting DNA is present before the switch.

Conclusions:

• The post-decision period in bacteriophage λ infection allows for a switch to lysis.
• The accumulation of regulatory protein Q is a key factor in this switch.
• The timing of DNA replication relative to Q accumulation influences the duration of this switchable period.