Quorum-sensing-mediated communication with its bacterial host informs the phage VP882 lysis-lysogeny decision

Abstract

Quorum sensing (QS) is a process of bacterial cell-to-cell communication facilitated by extracellular signaling molecules called autoinducers (AIs). AIs are synthesized and secreted and through group-wide detection, bacteria orchestrate collective cell behaviors. In Vibrio cholerae, one QS pathway consists of the receptor VqmA and the AI 3,5-dimethyl-pyrazin-2-ol (DPO). The vibriophage VP882 encodes a VqmA homolog (VqmAPhage) that can bind DPO. VqmAPhage-DPO binding is used in the phage VP882 lysis-lysogeny decision making process, meaning that the phage exploits host-derived information to modulate its own behaviors. Understanding how VqmAPhage competes with host VqmA for DPO binding and how this binding regulates lysis is important both for the development of broad-spectrum phage therapy based on phage VP882 and for understanding how phages generally incorporate host-derived information into their behaviors. I validated previous findings concerning the DPO-binding characteristics of VqmA and I made strides in optimizing the production and purification of VqmAPhage, laying the groundwork for experiments comparing the ligand binding affinities and specificities of the two receptors. Additionally, the VP882 gene gp60 is predicted to encode an important regulator of the phage VP882 lysis-lysogeny transition. My data indicate that gp60 plays a role in regulating the lysogenic lifestyle of phage VP882.