The Transcriptional Repressor, MtrR, of the mtrCDE Efflux Pump Operon of Neisseria gonorrhoeae Can Also Serve as an Activator of "off Target" Gene (glnE) Expression.

• Type of Material: Article
• Authors: Paul .J.T. Johnson, Emory University; William Shafer, Emory University
• Language: English
• Date: 2015-06
• Publisher: MDPI
• Publication Version: Final Published Version
• Copyright Statement: © 2015 by the authors
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.3390/antibiotics4020188
• Title of Journal or Parent Work: Antibiotics
• ISSN: 2079-6382
• Volume: 4
• Issue: 2
• Start Page: 188
• End Page: 197
• Grant/Funding Information: This work was supported by NIH grant R37 AI021150-30 and funds from a VA Merit Award, both awarded to W.M.S. W.M.S. is supported in part by a Senior Research Career Scientist Award from the Medical Research Service of the Department of Veterans Affairs.
• Keywords: transcriptional control; Neisseria gonorrhoeae; DNA-binding protein; glutamine biosynthesis; drug efflux
• Research Categories: Health Sciences, General; Biology, Microbiology

Abstract

MtrR is a well-characterized repressor of the Neisseria gonorrhoeae mtrCDE efflux pump operon. However, results from a previous transcriptional profiling study suggested that MtrR also represses or activates expression of at least sixty genes outside of the mtr locus. Evidence that MtrR can directly repress so-called "off target" genes has previously been reported; in particular, MtrR was shown to directly repress glnA, which encodes glutamine synthetase. In contrast, evidence for the ability of MtrR to directly activate expression of gonococcal genes has been lacking; herein, we provide such evidence. We now report that MtrR has the ability to directly activate expression of glnE, which encodes the dual functional adenyltransferase/deadenylase enzyme GlnE that modifies GlnA resulting in regulation of its role in glutamine biosynthesis. With its capacity to repress expression of glnA, the results presented herein emphasize the diverse and often opposing regulatory properties of MtrR that likely contributes to the overall physiology and metabolism of N. gonorrhoeae.