title: Evolutionary Remodeling of Bacterial Motility Checkpoint Control.
abstract: Regulatory networks play a central role in the relationship between genotype and phenotype in all organisms. However, the mechanisms that underpin the evolutionary plasticity of these networks remain poorly understood. Here, we used experimental selection for enhanced bacterial motility in a porous environment to explore the adaptability of one of the most complex networks known in bacteria. We found that the resulting phenotypic changes are mediated by adaptive mutations in several functionally different proteins, including multiple components of the flagellar motor. Nevertheless, this evolutionary adaptation could be explained by a single mechanism, namely remodeling of the checkpoint regulating flagellar gene expression. Supported by computer simulations, our findings suggest that the specific "bow-tie" topology of the checkpoint facilitates evolutionary tuning of the cost-benefit trade-off between motility and growth. We propose that bow-tie regulatory motifs, which are widespread in cellular networks, play a general role in evolutionary adaptation.
authors.affiliation: Max Planck Institute for Terrestrial Microbiology and LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg 35043, Germany.
authors.forename: Bin
authors.initials: B
authors.lastname: Ni
authors.affiliation: Max Planck Institute for Terrestrial Microbiology and LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg 35043, Germany.
authors.forename: Bhaswar
authors.initials: B
authors.lastname: Ghosh
authors.affiliation: Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg 69120, Germany.
authors.forename: Ferencz S
authors.initials: FS
authors.lastname: Paldy
authors.affiliation: Max Planck Institute for Terrestrial Microbiology and LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg 35043, Germany.
authors.forename: Remy
authors.initials: R
authors.lastname: Colin
authors.affiliation: LOEWE Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, Marburg 35043, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Heimerl
authors.affiliation: Max Planck Institute for Terrestrial Microbiology and LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg 35043, Germany; Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg 69120, Germany. Electronic address: victor.sourjik@synmikro.mpi-marburg.mpg.de.
authors.forename: Victor
authors.initials: V
authors.lastname: Sourjik
mesh_terms: D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D002633:Chemotaxis / Q000235:genetics; D004926:Escherichia coli / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D005407:Flagella / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D053263:Gene Regulatory Networks; D008854:Microscopy, Electron; D009154:Mutation; D010641:Phenotype; D011401:Promoter Regions, Genetic; D012808:Sigma Factor / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D012808:Sigma Factor; D015534:Trans-Activators; C090552:flhC protein, E coli; C063202:sporulation-specific sigma factors; C071266:FlgM protein, Bacteria
keywords: adaptation; bacteria; bow tie; evolution; flagella; microorganisms; network; optimization; selection; sigma factor