Understanding the physiological role of the small RNA RydC

Bianco, Colleen Marion

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https://hdl.handle.net/2142/108081 Copy

Description

Title

Understanding the physiological role of the small RNA RydC

Author(s)

Bianco, Colleen Marion

Issue Date

2020-01-23

Director of Research (if dissertation) or Advisor (if thesis)

Vanderpool, Carin K

Doctoral Committee Chair(s)

Vanderpool, Carin K

Committee Member(s)

• Cronan, John E
• Orlean, Peter A.B
• Metcalf, William W

Department of Study

Microbiology

Discipline

Microbiology

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Small RNA, Transcription Factors, Escherichia coli, Genetics, Genomics, Microbial Physiology, Protein-Nucleic Acid Interactions, Regulation of Gene Expression, RNA Biology, Signal Transduction

Abstract

This project aims to understand the physiological role of the small RNA (sRNA) RydC and the signals controlling RydC production. RydC was previously shown to stabilize cfa (cyclopropane fatty acid synthase) mRNA, resulting in higher levels of cyclopropane fatty acids in the cell membrane. Here, we show that additional sRNAs, ArrS and CpxQ, also directly regulate cfa post-transcriptionally. RydC and ArrS act through masking an RNase E cleavage site in the cfa mRNA 5' untranslated region (UTR), and both sRNAs post-transcriptionally activate cfa. In contrast, CpxQ binds to a different site in the cfa mRNA 5' UTR and represses cfa expression in a mechanism that is dependent on Rho-mediated premature transcription termination. Alteration of membrane lipid composition is a key mechanism for bacteria to survive low pH environments, and we show that cfa translation increases in an sRNA-dependent manner when cells are subjected to mild acid stress. To further elucidate the physiological role of RydC, we sought to identify the transcription factor responsible for rydC expression. We demonstrate that the uncharacterized GntR family transcriptional regulator YieP represses transcription of the rydC in both Escherichia coli and Salmonella. We identify genes whose expression are dependent on YieP and determine that YieP may be playing a role regulating in amino acid transport, carbon metabolism, and aerobic respiration. We demonstrate that rydC transcription varies depending on the carbon source cells are utilizing.

Graduation Semester

2020-05

Type of Resource

Thesis

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http://hdl.handle.net/2142/108081

Copyright and License Information

Copyright 2020 Colleen M. Bianco

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