Members of the Sinorhizobium meliloti ChvI regulon identified by a DNA binding screen

BMC Microbiology

Research Article

Trevor C Charles¹  Louise Bélanger² 

[1] Department of Biology, University of Waterloo, N2L 3G1, Waterloo, Ontario, Canada;Department of Biology, University of Waterloo, N2L 3G1, Waterloo, Ontario, Canada;Prevtec microbia inc., Saint-Hyacinthe, Québec, Canada;

关键词: Rhizobia;    Response regulator;    DNA-binding;    Exopolysaccharide;    Alfalfa nodulation;    chvI;    Signal transduction;    Transcriptional regulation;    DNA binding assay;   

DOI  :  10.1186/1471-2180-13-132

 received in 2012-10-09, accepted in 2013-02-08,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundThe Sinorhizobium meliloti ExoS/ChvI two component regulatory system is required for N2-fixing symbiosis and exopolysaccharide synthesis. Orthologous systems are present in other Alphaproteobacteria, and in many instances have been shown to be necessary for normal interactions with corresponding eukaryotic hosts. Only a few transcriptional regulation targets have been determined, and as a result there is limited understanding of the mechanisms that are controlled by the system.ResultsIn an attempt to better define the members of the regulon, we have applied a simple in vitro electrophoretic screen for DNA fragments that are bound by the ChvI response regulator protein. Several putative transcriptional targets were identified and three were further examined by reporter gene fusion experiments for transcriptional regulation. Two were confirmed to be repressed by ChvI, while one was activated by ChvI.ConclusionsOur results suggest a role for ChvI as both a direct activator and repressor of transcription. The identities and functions of many of these genes suggest explanations for some aspects of the pleiotropic phenotype of exoS and chvI mutants. This work paves the way for in depth characterization of the ExoS/ChvI regulon and its potential role in directing bacteria-host relationships.

【 授权许可】

CC BY   
© Bélanger and Charles; licensee BioMed Central Ltd. 2013