Events

Emily Bacon, Pharmaceutical Sciences graduate student (Peters Lab), will be defending her PhD research thesis:

Gene regulation and signal transduction in γ-proteobacteria

11:00 AM
Monday, July 29, 2024
6201 Microbial Sciences Building

Bacteria respond to environmental stresses through signal transduction pathways, by which the cell rapidly changes expression profiles of specific sets of genes that mitigate the stress. Due to the complexities of bacterial signal transduction, comprehensively understanding how stress inputs and the plethora of regulatory factors work together to modulate gene expression can be difficult. Even in model bacteria, where many of the individual components of signal transduction are known, we lack a detailed understanding of how genes work together at the pathway and process level to respond to stresses. Here we focus on signal transduction and gene regulation in γ-proteobacteria and in particular the non-model, antibiotic-resistant pathogen Acinetobacter baumannii. Understanding the distinct regulatory paradigms used by A. baumannii to mitigate cellular stresses may uncover new therapeutic targets. While many γ-proteobacteria use the extracytoplasmic function (ECF) σ factor, RpoE, to invoke envelope homeostasis networks in response to stress, at the outset of this work it was unclear if any ECF σ factors in A. baumannii play similar roles. In this thesis, I provide a comprehensive exploration into regulation by the Acinetobacter-specific ECF sigma factor, SigAb. My work reveals new physiological roles for SigAb and the SigAb-dependent small RNA SabS, provides a novel approach for assessing gene fitness using CRISPR-guided transposons, and highlights the distinct regulatory architecture of A. baumannii. Additionally, I developed replicative and integrative expression vectors alongside a novel, IPTG-inducible promoter for use in the model bacterium Escherichia coli K-12 as well as strains of A. baumannii and showed the utility of these expression systems for cross-species functional studies. Finally, I initiated development of a new genetic tool for systematic study of signal transduction and regulatory networks in γ-proteobacteria, called Reporter-CRISPRi. I envision that the tools developed, and knowledge gained in this thesis will serve as a foundation for dissecting gene regulation across Acinetobacter sp. and diverse bacteria.

Register to attend this PhD defense on Zoom