The Canadian Society of Microbiologists Ambassador Award Seminar
 
Seminar Title: Molecular and functional insights into the toxin-antitoxin systems of Legionella pneumophila

Abstract: Toxin-antitoxin (TA) systems are nearly ubiquitous yet enigmatic genetic elements in bacteria. They encode a protein toxin and neutralizing antitoxin, allowing them to act as cellular growth switches. Jordan’s research is focused on exploring the molecular diversity of TA systems in the bacterial pathogen Legionella pneumophila. He will describe an atypical tripartite module that, as a consequence of a gene fission event, has undergone considerable functional evolution despite retaining a high degree of structural congruence with its ancestral system. He will additionally discuss a TA system that is directly involved in L. pneumophila’s response to genotoxic stress. This module leads to cell death during DNA stress, however when it is deleted, cells enter a dormant state and display enhanced survival. Curiously, enhanced survival can be conferred from the deletion mutant to wild-type cells in a contact-dependent manner, and insights into the genetic pathways that underlie this phenomenon will be discussed.