Present address: Department of Molecular Genetics, National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia.
The ColR–ColS two-component signal transduction system is involved in regulation of Tn4652 transposition in Pseudomonas putida under starvation conditions
Article first published online: 30 SEP 2004
Volume 54, Issue 3, pages 795–807, November 2004
How to Cite
Hõrak, R., Ilves, H., Pruunsild, P., Kuljus, M. and Kivisaar, M. (2004), The ColR–ColS two-component signal transduction system is involved in regulation of Tn4652 transposition in Pseudomonas putida under starvation conditions. Molecular Microbiology, 54: 795–807. doi: 10.1111/j.1365-2958.2004.04311.x
- Issue published online: 30 SEP 2004
- Article first published online: 30 SEP 2004
- Accepted 15 July, 2004.
Bacteria use two-component signal transduction pathways to sense both extracellular and intracellular environment and to coordinate cellular events according to changing conditions. Adaptation can be either physiological or genetical. Here, we present evidence that a genome reorganization process such as transposition can be controlled by certain environmental cues sensed by a two-component signal transduction system. We demonstrate that transposition-dependent accumulation of phenol-utilizing mutants is severely decreased in Pseudomonas putida defective in a two-component system colRS. Translocation of Tn4652 is decreased both in colR- and colS-defective strains, indicating that signal transduction from a histidine kinase ColS to a response regulator ColR is necessary for the activation of Tn4652 in bacteria starving on phenol. However, overexpression of ColR in a colS-defective strain restores Tn4652 transposition, suggesting that absence of the signal from ColS can be compensated by an elevated amount of ColR. In vitro analysis of purified ColR and ColS proteins evidenced that they constitute a functional phosphorelay. Site-directed mutagenesis revealed that a conserved H221 can be the phosphoryl-accepting residue in ColS and that aspartate residues D8 and D51 of ColR are necessary for the phosphotransfer from ColS to ColR. To our knowledge, Tn4652 is the first bacterial transposon regulated by a two-component system. This finding indicates that transpositional activity can respond to signals sensed and processed by the host.