An Epigenetic Switch Involving Overlapping Fur and DNA Methylation Optimizes Expression of a Type VI Secretion Gene Cluster
2011

How Iron and Methylation Control a Bacterial Gene Switch

publication Evidence: high

Author Information

Author(s): Brunet Yannick R., Bernard Christophe S., Gavioli Marthe, Lloubès Roland, Cascales Eric

Primary Institution: Laboratoire d'Ingénierie des Systèmes Macromoléculaires, CNRS – UPR 9027, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université, Marseille, France

Hypothesis

What is the regulatory mechanism controlling expression of the enteroaggregative Escherichia coli sci1 T6SS gene cluster?

Conclusion

The expression of the sci1 Type VI secretion gene cluster is regulated by an epigenetic switch influenced by iron availability and DNA methylation.

Supporting Evidence

  • The study identified Fur as the main regulator of the sci1 T6SS gene cluster.
  • Fur binding prevents methylation at a specific GATC site, influencing gene expression.
  • In iron-limited conditions, Fur is relieved from the promoter, allowing gene expression.

Takeaway

Bacteria can turn certain genes on or off based on the amount of iron available and some chemical changes to their DNA, which helps them adapt to their environment.

Methodology

The study used reporter fusion, gel shift, and in vivo and in vitro methylation assays to analyze the regulatory role of Fur and Dam-dependent methylation.

Digital Object Identifier (DOI)

10.1371/journal.pgen.1002205

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