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The Escherichia coli MarA protein regulates the ycgZ ‐ ymgABC operon to inhibit biofilm formation
Author(s) -
Kettles Rachel A.,
Tschowri Natalia,
Lyons Kevin J.,
Sharma Prateek,
Hengge Regine,
Webber Mark A.,
Grainger David C.
Publication year - 2019
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.14386
Subject(s) - biology , operon , escherichia coli , biofilm , microbiology and biotechnology , escherichia coli proteins , bacteria , biochemistry , gene , genetics
Summary The Escherichia coli marRAB operon is a paradigm for chromosomally encoded antibiotic resistance. The operon exerts its effect via an encoded transcription factor called MarA that modulates efflux pump and porin expression. In this work, we show that MarA is also a regulator of biofilm formation. Control is mediated by binding of MarA to the intergenic region upstream of the ycgZ ‐ ymgABC operon. The operon, known to influence the formation of curli fibres and colanic acid, is usually expressed during periods of starvation. Hence, the ycgZ ‐ ymgABC promoter is recognised by σ 38 (RpoS)‐associated RNA polymerase (RNAP). Surprisingly, MarA does not influence σ 38 ‐dependent transcription. Instead, MarA drives transcription by the housekeeping σ 70 ‐associated RNAP. The effects of MarA on ycgZ ‐ ymgABC expression are coupled with biofilm formation by the rcsCDB phosphorelay system, with YcgZ, YmgA and YmgB forming a complex that directly interacts with the histidine kinase domain of RcsC.