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- Title
A small protein that mediates the activation of a two-component system by another two-component system.
- Authors
Kox, Linda F. F.; Wösten, Marc M. S. M.; Groisman, Eduardo A.
- Abstract
The PmrA-PmrB two-component system of Salmonella enterica controls resistance to the peptide antibiotic polymyxin B and to several antimicrobial proteins from human neutrophils. Transcription of PmrA-activated genes is induced by high iron, but can also be promoted by growth in low magnesium in a process that requires another two-component system, PhoP-PhoQ. Here, we define the genetic basis for the interaction between the PhoP-PhoQ and PmrA-PmrB systems. We have identified pmrD as a PhoP-activated gene that mediates the transcriptional activation of PmrA-regulated genes during growth in low magnesium. When transcription of pmrD is driven from a heterologous promoter, expression of PintA-activated genes occurs even at repressing magnesium concentrations and becomes independent of the phoP and phoQ genes. The PmrD effect is specific for PmrA-regulated genes and requires functional PmrA and PmrB proteins. A pmrD mutant is sensitive to polymyxin if grown in low magnesium, but resistant if grown in high iron. The PmrD protein controls the activity of the PmrA-PmrB system at a post-transcriptional level.
- Subjects
MAGNESIUM; CELLULAR signal transduction; SALMONELLA enteritidis; PEPTIDE antibiotics; POLYMYXIN; NEUTROPHILS; PROTEINS
- Publication
EMBO Journal, 2000, Vol 19, Issue 8, p1861
- ISSN
0261-4189
- Publication type
Article
- DOI
10.1093/emboj/19.8.1861