Faculty Collaboration Database

A Rex family transcriptional repressor influences H2O2 accumulation by Enterococcus faecalis. J Bacteriol 2013 Apr;195(8):1815-24

Date

02/19/2013

Pubmed ID

23417491

Pubmed Central ID

PMC3624565

DOI

10.1128/JB.02135-12

Scopus ID

2-s2.0-84876088340 (requires institutional sign-in at Scopus site)   55 Citations

Abstract

Rex factors are bacterial transcription factors thought to respond to the cellular NAD(+)/NADH ratio in order to modulate gene expression by differentially binding DNA. To date, Rex factors have been implicated in regulating genes of central metabolism, oxidative stress response, and biofilm formation. The genome of Enterococcus faecalis, a low-GC Gram-positive opportunistic pathogen, encodes EF2638, a putative Rex factor. To study the role of E. faecalis Rex, we purified EF2638 and evaluated its DNA binding activity in vitro. EF2638 was able to bind putative promoter segments of several E. faecalis genes in an NADH-responsive manner, indicating that it represents an authentic Rex factor. Transcriptome analysis of a ΔEF2638 mutant revealed that genes likely to be involved in anaerobic metabolism were upregulated during aerobic growth, and the mutant exhibited an altered NAD(+)/NADH ratio. The ΔEF2638 mutant also exhibited a growth defect when grown with aeration on several carbon sources, suggesting an impaired ability to cope with oxidative stress. Inclusion of catalase in the medium alleviated the growth defect. H(2)O(2) measurements revealed that the mutant accumulates significantly more H(2)O(2) than wild-type E. faecalis. In summary, EF2638 represents an authentic Rex factor in E. faecalis that influences the production or detoxification of H(2)O(2) in addition to its more familiar role as a regulator of anaerobic gene expression.

Author List

Vesić D, Kristich CJ

Authors

Dusanka Djoric Research Scientist I in the Microbiology and Immunology department at Medical College of Wisconsin
Christopher J. Kristich PhD Professor in the Microbiology and Immunology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Bacterial Proteins
Enterococcus faecalis
Fermentation
Gene Expression Regulation, Bacterial
Genome, Bacterial
Homeostasis
Hydrogen Peroxide
Mutation
NAD
Oxidation-Reduction
Protein Array Analysis
Protein Binding
Repressor Proteins
Transcriptome