Dormant phages communicate via arbitrium to control exit from lysogeny

Area of Science:

• Microbiology
• Virology
• Molecular Biology

Background:

• Temperate bacterial viruses (phages) can enter either lysis or lysogeny.
• Phage arbitrium peptide signaling regulates entry into lysogeny in naive cells.
• The role of arbitrium signaling in phage induction (exit from lysogeny) is unknown.

Purpose of the Study:

• To investigate if arbitrium signaling regulates phage induction from lysogeny.
• To determine how DNA damage and arbitrium signaling interact to control phage fate.
• To assess the impact of prophage signaling on infecting phages.

Main Methods:

• Studied arbitrium signal secretion and sensing by prophages.
• Analyzed DNA damage-dependent phage induction rates.
• Investigated the regulation of the arbitrium-responsive gene aimX.
• Assessed the effect of prophage signaling on infecting phage lysogeny decision.

Main Results:

• Arbitrium-coding prophages communicate, repressing DNA damage-induced phage induction.
• Signaling reduces induction rates when lysogen density is high.
• DNA damage and communication converge to regulate aimX expression or occur downstream.
• Prophage signaling promotes lysogeny in nearby infecting phages.

Conclusions:

• Phages utilize arbitrium signaling throughout their life cycle.
• Communication allows phages to sense lysogen population density.
• This sensing mechanism optimizes the lysis-lysogeny decision, favoring dormancy in high-lysogen environments.