Involvement of cpxA, a sensor of a two-component regulatory system, in the pH-dependent regulation of expression of Shigella sonnei virF gene.
AUTOR(ES)
Nakayama, S
RESUMO
In Shigella species, IpaBCD proteins encoded on the virulence plasmid direct the entry of this bacterium into host epithelial cells. Expression of the ipaBCD genes is under the control of several environmental conditions, such as temperature and osmolarity. Extracellular pH also controlled the the expression of the genes, and this regulation occurred mainly at the step of expression of virF, a plasmid-encoded positive regulator of ipaBCD. The expression of virF was activated at high pH (pH 7.4) and repressed at low pH (pH 6.0). We isolated a Tn10 transposon mutant in Escherichia coli K-12 which altered this regulation at the transcriptional level. The Tn10 in the mutant inserted within a reading frame of the cpxA gene, whose product belongs to a family of sensor proteins of two-component signal transduction systems. Complementation analysis showed that cpxA was involved in the pH-dependent regulation of virF gene expression. A gene homologous to cpxA was conserved in Shigella spp. as well as in E. coli. These results may indicate that CpxA senses directly or indirectly a change in extracellular pH and influences the expression of virF in E. coli and Shigella spp.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=177285Documentos Relacionados
- A Sensor of the Two-Component System CpxA Affects Expression of the Type III Secretion System through Posttranscriptional Processing of InvE
- Identification of cpxR as a Positive Regulator Essential for Expression of the Shigella sonnei virF Gene
- Cpx Two-Component Signal Transduction in Escherichia coli: Excessive CpxR-P Levels Underlie CpxA* Phenotypes
- Regulation of Membrane Permeability by a Two-Component Regulatory System in Pseudomonas aeruginosa
- The two-component regulatory system ompR-envZ controls the virulence of Shigella flexneri.