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A forward genetic screen identifies new host factors influencing bacteriophage lambda's lysis-lysogeny decision

In order to survive, organisms must integrate internal and external signals via complex signaling pathways to intelligently navigate their environment. Bacteriophage lambda has long been a classic model for understanding such pathways, and how they allow cells to effect changes in physiology in order to adapt to varying circumstances. When infecting its host Escherichia coli, phage lambda may either make more viruses (lysis), or integrate itself into the host genome (lysogeny). To better understand the extent to which host physiology influences the lysis-lysogeny decision, I performed a forward genetic screen to identify genes whose deletions bias the infected cell towards lysis or lysogeny. This screen revealed numerous host-encoded genes linked to the lysis-lysogeny decision, including transcription factors and genes in metabolic pathways. These results demonstrate previously unknown links between host physiology and viral decision-making, shedding new light on this classic model system.