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Updated: May 11, 2026

The Multifaceted Benefits of Protein Co-expression in Escherichia coli
Published on: February 5, 2015
Enterococcal Rgg-like regulator ElrR activates expression of the elrA operon
Romain Dumoulin1, Naima Cortes-Perez, Stephane Gaubert
1INRA, UMR1319 Micalis, Jouy-en-Josas, France.
Abstract:
The Enterococcus faecalis leucine-rich protein ElrA promotes virulence by stimulating bacterial persistence in macrophages and production of the interleukin-6 (IL-6) cytokine. The ElrA protein is encoded within an operon that is poorly expressed under laboratory conditions but induced in vivo. In this study, we identify ef2687 (renamed elrR), which encodes a member of the Rgg (regulator gene for glucosyltransferase) family of putative regulatory proteins. Using quantitative reverse transcription-PCR, translational lacZ fusions, and electrophoretic mobility shift assays, we demonstrate that ElrR positively regulates expression of elrA. These results correlate with the attenuated virulence of the ΔelrR strain in a mouse peritonitis model. Virulence of simple and double elrR and elrA deletion mutants also suggests a remaining ElrR-independent expression of elrA in vivo and additional virulence-related genes controlled by ElrR.
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