Elucidating the Evolution and Function of sRNAs that Facilitate Bacterial Stress Tolerance

Author

Madeline Claire Krieger, Portland State UniversityFollow

Sponsor

Portland State University. Department of Biology

First Advisor

Justin Courcelle

Term of Graduation

Summer 2021

Date of Publication

6-28-2021

Document Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.) in Biology

Department

Biology

Language

English

Subjects

Non-coding RNA, Oxidative stress, Streptococcus mutans, Gene expression

DOI

10.15760/etd.7621

Physical Description

1 online resource (vi, 193 pages)

Abstract

Non-coding small RNAs (sRNAs) are ubiquitous post-transcriptional regulators found in both gram-negative and gram-positive bacteria. Despite their integral role in many regulatory pathways, including those that facilitate stress-tolerance, little is known about the evolutionary forces that drive the emergence of novel sRNAs, how prevalent sRNAs are within bacterial species, or the functions of a majority of these transcripts. In this work, I first describe the evolution of OxyS, a well-characterized sRNA in gram-negative Enterobacteriaceae that is involved in coordinating the bacterial response to oxidative stress. Next, I identify novel sRNAs differentially produced by the gram-positive oral pathogen Streptococcus mutans in response to multiple stress conditions. Finally, I investigate the function of one novel sRNA, SmsR4, in fine-tuning sugar-alcohol metabolism in S. mutans. These findings reveal protein coding genes to be a new reservoir for sRNA emergence and define a novel evolutionary path through which new sRNAs become incorporated into regulatory networks. Additionally, I show evidence for abundant regulation by sRNAs in S. mutans during a variety of stress responses and outline how SmsR4 participates in the regulation of sugar metabolism. Taken together, this work presents a new paradigm for sRNA emergence from protein coding genes and demonstrates the prevalence and utility of the understudied phenomenon of post-transcriptional regulation in oral bacteria.

Rights

©2021 Madeline Claire Krieger

In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).

Persistent Identifier

https://archives.pdx.edu/ds/psu/36264

Recommended Citation

Krieger, Madeline Claire, "Elucidating the Evolution and Function of sRNAs that Facilitate Bacterial Stress Tolerance" (2021). Dissertations and Theses. Paper 5749.
https://doi.org/10.15760/etd.7621