High impact information on expE1

• This phenotype was shown to be dependent on the exoB and expE genes required for synthesis of exopolysaccharide II in R. meliloti but not to be dependent on genes required exclusively for the synthesis of the succinoglycan or exopolysaccharide I [1].
• High-pressure liquid chromatographic fractionation of S. meliloti culture filtrate extracts revealed at least three peaks with AHL activity, one of which activated ExpR-dependent expression of the expE operon [2].
• Heterologous expression of lacZ transcriptional fusions of the expE promoters has shown that genetic background is more important that promoter sequence for exp gene expression, since expE promoters from both strains are expressed at high level in EFB1 and not in SU47 [3].
• However, sequence divergence occurs in a putative expE promoter region [4].

References