Competitive and cooperative effects in quorum-sensing-regulated galactoglucan biosynthesis in Sinorhizobium meliloti.

ABSTRACT: The symbiotic nitrogen-fixing bacterium Sinorhizobium meliloti possesses the Sin quorum-sensing system based on N-acyl homoserine lactones (AHLs) as signal molecules. The Sin system consists of SinI, the AHL synthase, and SinR, the LuxR-type regulator. This system regulates the expression of a multitude of S. meliloti genes through ExpR, another LuxR-type regulator. Analysis of the activity of the sinI promoter showed that the expression of sinI is dependent on sinR and enhanced by a combination of expR and Sin AHLs. The characterization of the ExpR binding site upstream of sinI and the identification of binding sites upstream of the galactoglucan biosynthesis genes wgaA (expA1) and wgeA (expE1) allowed the definition of a consensus sequence for these binding sites. Based on this consensus

SUBMITTER: McIntosh M 

PROVIDER: S-EPMC2493264 | biostudies-literature | 2008 Aug

REPOSITORIES: biostudies-literature