Dissecting the genetic components of adaptation of Escherichia coli to the mouse gut.
While pleiotropic adaptive mutations are thought to be central for evolution, little is known on the downstream molecular effects allowing adaptation to complex ecologically relevant environments. Here we show that Escherichia coli MG1655 adapts rapidly to the intestine of germ-free mice by single point mutations in EnvZ/OmpR two-component signal transduction system, which controls more than 100 genes. The selective advantage conferred by the mutations that modulate EnvZ/OmpR activities was the result of their independent and additive effects on flagellin expression and permeability. These results obtained in vivo thus suggest that global regulators may have evolved to coordinate activities that need to be fine-tuned simultaneously during adaptation to complex environments and that mutations in such regulators permit adjustment of the boundaries of physiological adaptation when switching between two very distinct environments.
Giraud
Antoine
A
INSERM, U571, Paris, France. antoine.giraud@imbim.uu.se
Arous
Safia
S
De Paepe
Marianne
M
Gaboriau-Routhiau
Valérie
V
Bambou
Jean-Christophe
JC
Rakotobe
Sabine
S
Lindner
Ariel B
AB
Taddei
François
F
Cerf-Bensussan
Nadine
N
D000222:Adaptation, Physiological / Q000235:genetics*; D000818:Animals; D015415:Biomarkers; D002463:Cell Membrane Permeability / Q000235:genetics; D002876:Chromosomes, Bacterial; D018076:DNA, Complementary / Q000096:biosynthesis; D048168:Escherichia coli K12 / Q000235:genetics* / Q000502:physiology*; D005408:Flagellin / Q000096:biosynthesis / Q000235:genetics; D041981:Gastrointestinal Tract / Q000382:microbiology*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D017930:Genes, Reporter; D015698:Genomic Library; D005856:Germ-Free Life; D049452:Green Fluorescent Proteins / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D008958:Models, Molecular; D020125:Mutation, Missense; D010957:Plasmids; D017354:Point Mutation; D018272:Porins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D018085:Regulon; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA
D015415:Biomarkers; D018076:DNA, Complementary; D018272:Porins; D005408:Flagellin; D049452:Green Fluorescent Proteins