Gene expression regulation by the Curli activator CsgD protein: modulation of cellulose biosynthesis and control of negative determinants for microbial adhesion.

Negative Determinants for Microbial Cellulose Biosynthesis and Control of Activator CsgD Protein: Modulation of Gene Expression Regulation by the Curli

The curli biosynthesis regulator CsgD co-ordinates the expression of both positive and negative determinants for biofilm formation in Escherichia coli.

Production of curli, extracellular structures important for biofilm formation, is positively regulated by OmpR, which constitutes with the EnvZ protein an osmolarity-sensing two-component regulatory system. The expression of curli is cryptic in most Escherichia coli laboratory strains such as MG1655, due to the lack of csgD expression. The csgD gene encodes a transcription activator of the curl...

Cellulose modulates biofilm formation by counteracting curli-mediated colonization of solid surfaces in Escherichia coli.

In enterobacteria, the CsgD protein activates production of two extracellular structures: thin aggregative fimbriae (curli) and cellulose. While curli fibres promote biofilm formation and cell aggregation, the evidence for a direct role of cellulose as an additional determinant for biofilm formation is not as straightforward. The MG1655 laboratory strain of Escherichia coli only produces limite...

Two antisense RNAs target the transcriptional regulator CsgD to inhibit curli synthesis.

Escherichia coli produces proteinaceous surface structures called curli that are involved in adhesion and biofilm formation. CsgD is the transcriptional activator of curli genes. We show here that csgD expression is, in part, controlled post-transcriptionally by two redundant small RNAs (sRNAs), OmrA and OmrB. Their overexpression results in curli deficiency, in accordance with the inhibition o...

Production of cellulose and curli fimbriae by members of the family Enterobacteriaceae isolated from the human gastrointestinal tract.

Citrobacter spp., Enterobacter spp., and Klebsiella spp. isolated from the human gut were investigated for the biosynthesis of cellulose and curli fimbriae (csg). While Citrobacter spp. produced curli fimbriae and cellulose and Enterobacter spp. produced cellulose with various temperature-regulatory programs, Klebsiella spp. did not show pronounced expression of those extracellular matrix compo...