The Escherichia coli multiple antibiotic resistance activator protein represses transcription of the lac operon

Biochem Soc Trans. 2019 Apr 30;47(2):671-677. doi: 10.1042/BST20180498. Epub 2019 Mar 8.

Abstract

In Escherichia coli, the marRAB operon is a determinant for antibiotic resistance. Such phenotypes require the encoded transcription factor MarA that activates efflux pump expression. To better understand all genes controlled by MarA, we recently mapped binding of the regulator across the E. coli genome. As expected, many MarA targets were adjacent to genes encoding stress response systems. Surprisingly, one MarA-binding site overlapped the lac operon regulatory region. Here, we show that MarA specifically targets this locus and can block transcription of the lac genes. Repression is mediated by binding of MarA to a site overlapping the lacP1 promoter -35 element. Control of the lac operon by MarA does not impact antibiotic resistance.

Keywords: antibiotic; lac operon; regulation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Drug Resistance, Microbial / genetics
  • Escherichia coli / drug effects
  • Escherichia coli / genetics*
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism
  • Lac Operon / genetics*
  • Promoter Regions, Genetic / drug effects
  • Promoter Regions, Genetic / genetics
  • Transcription, Genetic / drug effects
  • Transcription, Genetic / genetics

Substances

  • Anti-Bacterial Agents
  • Escherichia coli Proteins