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

BMC Microbiology

Trevor C Charles²  Louise Bélanger¹ 

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

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

Others  :  1143625
DOI  :  10.1186/1471-2180-13-132

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

【 摘 要 】

Background

The 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.

Results

In 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.

Conclusions

Our 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】

   
2013 Bélanger and Charles; licensee BioMed Central Ltd.

【 图 表 】

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