Title: Characterizing Legionella pneumophila's evasion of amoeba immunity
Abstract:
Harmless bacteria can become human pathogens via selection from their environmental hosts, bacterivores. Bacterivores are microeukaryotes which prey on bacteria for food and use many of the same innate immune pathways as human immune cells. When bacteria undergo selection from these hosts, they can evolve mechanisms to overcome these conserved immune pathways. This selection can result in bacteria able to circumvent human innate immunity. However, what this selection looks like on the molecular level is still poorly understood.
To investigate what molecules may be interacting between bacteria and bacteriovores, the bacterivore Dictyostelium Discoideum (Dd) can be infected with a transposon library of Legionella pneumophila (Lp). This will identify Lp genes required for infection of Dd. Then, by preforming this experiment in different Dd mutants, specific interactors between the host and pathogen can be identified. For example, by infecting Dd which lack the iron transporter Nramp, we can identify Lp genes involved in the host-pathogen battle for iron.
This in-progress screen has already identified a handful candidates which may be important for Lp’s infection of Dd. Three of these are secreted by Lp’s Type II Secretion system (T2SS), which secretes proteins into the Legionella Containing Vacuole (LCV). The role of the T2SS during Lp infection is not well characterized. To investigate the roles of these three candidates, KOs were generated and used to infect Dd. Based on the results of this validation, we can investigate where these proteins localize to and what roles they may play in Lp’s host takeover.
Levin Lab
Friday, October 27th, 2023
12:00PM
Langley A219B