Lipid A modifications in Bordetella pertussis : regulation and function of the lgm locus
department or school: Science, Faculty of
department or school: Microbiology and Immunology, Department of
data provider: DSpace
degree campus: UBCV
creator: Ifill, Gyles Anderson
issued: 2023-01-31T08:00:00Z
issued: 2022
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: In many Gram-negative pathogens, gene transcription is often facilitated by post-transcriptional regulatory mechanisms. In Bordetella pertussis, several regulatory RNAs have been identified, but their targets and impacts on virulence factor production have not been assessed. RNase III and RNase E, endonucleases with dominant roles in regulatory RNA processing, were mutated in B. pertussis to determine gene loci regulated at the post-transcriptional level. RNA-Seq analysis of these strains identified that ~25% of the B. pertussis transcriptome was affected in each endonuclease mutant. Substantial impacts were observed on genes associated with amino acid uptake, bacterial secretion, and many virulence factors. Comparing these findings to the regulon of the RNA chaperone Hfq, 120 genes, and 19 operons were identified as potentially influenced at the post-transcriptional level. Amongst these, the lipid A glucosamine modification (lgm) locus was one of the most upregulated gene loci in the RNase E mutant strain. The lgm locus is a 5 gene operon consisting of four genes in one orientation (lgmA-D) and a fifth open reading frame (lgmE) overlapping in the opposite orientation. Given lipid A modifications in Gram-negative bacteria are typically controlled by complex regulatory networks, it was proposed that several overlapping systems are involved in lgm locus regulation, including the role of a cis-encoded antisense RNA. As shown by luciferase reporter assays, the lgm locus responds to Bvg phase, nutrient availability, low pH, and increased C02%. These assays also identified a reciprocal relationship in activation of the diametrically opposed lgmA and lgmE promoters, suggestive of asRNA regulation. It was then proposed that lgmE acts as dual-function RNA as the lgmE ORF has all the characteristics of a translated protein. It is shown that lgmE encodes a functional, small membrane-associated protein, and deletion and overexpression of lgmE negatively impact lgm locus activit…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/80589
note: Lipid A modifications in Bordetella pertussis: Regulation and Function of the lgm Locus by Gyles Anderson Ifill B.Sc., The University of East Anglia, 2014 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Microbiology and Immunology) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) December 2021 © Gyles Anderson Ifill, 2021 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the dissertation entitled: Lipid A modifications in Bordetella pertussis: regulation and function of the lgm locus submitted by Gyles A. Ifill in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Microbiology and Immunology Examining Committee: Professor Rachel C. Fernandez, Microbiology and Immunology, UBC Supervisor Professor J. Thomas Beatty, Microbiology and Immunology, UBC Supervisory Committee Member Professor Rosie J. Redfield, Zoology, UBC University Examiner Associate Professor Cara H. Haney, Microbiology and Immunology, UBC University Examiner Additional Supervisory Committee Members: Professor Charles J. Thompson, Microbiology and Immunology, UBC Supervisory Committee Member Professor Natalie C. J. Strynadka, Biochemistry and Molecular Biology, UBC Supervisory Committee Member iii Abstract In many Gram-negative pathogens, gene transcription is often facilitated by post-transcriptional regulatory mechanisms. In Bordetella pertussis, several regulatory RNAs have been identified, but their targets and impacts on virulence factor production have not been assessed. RNase III and RNase E, endonucleases with dominant roles in regulatory RNA processing, were mutated in B. pertussis to determine gene loci regulated at the post-transcriptional level. RNA-Seq analysis of these strains identified that ~25% of the B. pertussis transcriptome was affected in each endonuclease mutan…
has type: Thesis/Dissertation
date issued: 2022-05
is shown at: 10.14288/1.0406206
language: eng
degree discipline: Microbiology and Immunology
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Fernandez, Rachel C.
type: Text
identifier URI: http://hdl.handle.net/2429/80589