Transcription factor function and promoter architecture govern the evolution of bacterial regulons

Proc Natl Acad Sci U S A. 2009 Mar 17;106(11):4319-24. doi: 10.1073/pnas.0810343106. Epub 2009 Feb 27.

Abstract

Evolutionary changes in ancestral regulatory circuits can bring about phenotypic differences between related organisms. Studies of regulatory circuits in eukaryotes suggest that these modifications result primarily from changes in cis-regulatory elements (as opposed to alterations in the transcription factors that act upon these sequences). It is presently unclear how the evolution of gene regulatory circuits has proceeded in bacteria, given the rampant effects of horizontal gene transfer, which has significantly altered the composition of bacterial regulons. We now demonstrate that the evolution of the regulons governed by the regulatory protein PhoP in the related human pathogens Salmonella enterica and Yersinia pestis has entailed functional changes in the PhoP protein as well as in the architecture of PhoP-dependent promoters. These changes have resulted in orthologous PhoP proteins that differ both in their ability to promote transcription and in their role as virulence regulators. We posit that these changes allow bacterial transcription factors to incorporate newly acquired genes into ancestral regulatory circuits and yet retain control of the core members of a regulon.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteria / genetics*
  • Bacterial Proteins / physiology
  • Biological Evolution*
  • Gene Regulatory Networks
  • Humans
  • Promoter Regions, Genetic*
  • Regulatory Sequences, Nucleic Acid
  • Regulon / genetics*
  • Salmonella enterica / genetics
  • Transcription Factors / physiology*
  • Yersinia pestis / genetics

Substances

  • Bacterial Proteins
  • Transcription Factors
  • PhoP protein, Bacteria