Expression of the Escherichia coli ompW colicin S4 receptor gene is regulated by temperature and modulated by the H-NS and StpA nucleoid-associated proteins.
The OmpW family consists of a ubiquitous group of small outer membrane (OM) β-barrel proteins of Gram-negative bacteria with proposed roles in environmental adaptation but poorly understood mechanisms of expression. We report here that Escherichia coli K-12 OmpW contents are drastically modified by temperature changes compatible with the leap from the environment to warm-blooded hosts and/or vice versa. Thus, while OmpW is present in the OM of bacteria grown at 37 °C, it sharply disappears at 23 °C with the concomitant acquisition of colicin S4 resistance by the cells. ompW::lacZY fusions indicated that temperature regulation operates at the level of transcription, being ompW expression almost abolished at 23 °C as compared to 37 °C. Moreover, E. coli Δhns mutants lacking H-NS showed reductions in ompW transcription and OmpW contents at 37 °C, indicating positive modulatory roles for this nucleoid-structuring protein in ompW expression. Also, ΔhnsΔstpA double mutants simultaneously lacking H-NS and its paralog StpA showed more severe reductions in ompW expression at 37 °C, resulting in the complete loss of OmpW. The overall results indicate that OmpW contents in E. coli are regulated by both temperature and H-NS and reinforce OmpW functions in bacterial adaptation to warm-blooded hosts.
Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET) and Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario, Argentina.
Luciano
L
Brambilla
Jorgelina
J
Morán-Barrio
Alejandro M
AM
Viale
D019677:Artificial Gene Fusion; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D048168:Escherichia coli K12 / Q000235:genetics* / Q000528:radiation effects; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism*; D036781:Fimbriae Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D013696:Temperature; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000032:analysis / Q000235:genetics
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C529458:FimG protein, E coli; C031908:H-NS protein, bacteria; D018832:Molecular Chaperones; C090104:StpA protein, E coli; C064035:ompW protein, E coli; D036781:Fimbriae Proteins; D001616:beta-Galactosidase
H-NS; OmpW; StpA; outer membrane protein; temperature regulation