Gene expression patterns and differential input into curli fimbriae regulation of all GGDEF/EAL domain proteins in Escherichia coli

Abstract

Switching from the motile planktonic bacterial lifestyle to a biofilm existence is stimulated by the signalling molecule bis-(3′-5′)-cyclic-diguanosine monophosphate (cyclic-di-GMP), which is antagonistically controlled by diguanylate cyclases (DGCs; characterized by GGDEF domains) and specific phosphodiesterases (PDEs; mostly featuring EAL domains). Here, we present the expression patterns of all 28 genes that encode GGDEF/EAL domain proteins in Escherichia coli K-12. Twenty-one genes are expressed in Luria–Bertani medium, with 15 being under σ S control. While a small subset of GGDEF/EAL proteins (YeaJ and YhjH) is dominant and modulates motility in post-exponentially growing cells, a diverse battery of GGDEF/EAL proteins is deployed during entry into stationary phase, especially in cells grown at reduced temperature (28 °C). This suggests that multiple signal input into cyclic-di-GMP control is particularly important in growth-restricted cells in an extra-host environment. Six GGDEF/EAL genes differentially control the expression of adhesive curli fimbriae. Besides the previously described ydaM, yciR, yegE and yhjH genes, these are yhdA (csrD), which stimulates the expression of the DGC YdaM and the major curli regulator CsgD, and yeaP, which contributes to expression of the curli structural operon csgBAC. Finally, we discuss why other GGDEF/EAL domain-encoding genes, despite being expressed, do not influence motility and/or curli formation.

Comprehensive overexpression analysis of cyclic-di-GMP signalling proteins in the phytopathogen Pectobacterium atrosepticum reveals diverse effects on motility and virulence phenotypes

“…This in turn leads to asymmetrical inheritance of the chemotaxis machinery (Kulasekara et al, 2013). Therefore, discreet spatial and temporal pockets of changing c-di-GMP concentrations may mask the phenotypes caused by certain DGCs or PDEs when analysed on a global scale (Sommerfeldt et al, 2009;Tuckerman et al, 2009).…”

The diguanylate cyclase YddV controls production of the exopolysaccharide poly-N-acetylglucosamine (PNAG) through regulation of the PNAG biosynthetic pgaABCD operon

“…Recently, we have shown that YddV can affect the expression of curli-encoding genes (Tagliabue et al, 2010), which, however, are extremely sensitive to perturbations in intracellular c-di-GMP concentrations (Sommerfeldt et al, 2009). In this work, we show that overexpression of YddV, but not of other DGCs, stimulates production of poly-Nacetylglucosamine (PNAG), an EPS able to promote biofilm formation, by triggering expression of pgaABCD, the PNAG biosynthetic operon.…”

“…In addition, c-di-GMP biosynthesis affects important cellular processes, such as morphological differentiation and cell replication in Caulobacter crescentus (Paul et al, 2004), cell motility (Méndez-Ortiz et al, 2006;Jonas et al, 2008) and virulence factor production (Kulasakara et al, 2006;Hammer & Bassler, 2009). In Enterobacteria, c-di-GMP seems to be involved in regulation of adhesion factors, such as curli and cellulose, important for adaptation and survival outside the warm-blooded host (Simm et al, 2004;Kader et al, 2006;Weber et al, 2006;Solano et al, 2009), as also suggested by the observation that expression of the several diguanylate cyclase (DGC)-encoding genes is turned on at a growth temperature of 30 u C or lower (Weber et al, 2006;Sommerfeldt et al, 2009). Intracellular levels of c-di-GMP are regulated by two classes of isoenzymes: DGCs (c-di-GMP biosynthetic enzymes), also termed GGDEF proteins from the conserved Gly-Gly-AspGlu-Phe motif in their catalytic domains, and c-di-GMP phosphodiesterases (PDEs), which degrade c-di-GMP (Cotter & Stibitz, 2007).…”

“…The YddV protein is arguably one of the most expressed DGCs in Escherichia coli (Sommerfeldt et al, 2009). Recently, we have shown that YddV can affect the expression of curli-encoding genes (Tagliabue et al, 2010), which, however, are extremely sensitive to perturbations in intracellular c-di-GMP concentrations (Sommerfeldt et al, 2009).…”

“…Sommerfeldt et al, 2009). Intracellular levels of c-di-GMP are regulated by two classes of isoenzymes: DGCs (c-di-GMP biosynthetic enzymes), also termed GGDEF proteins from the conserved Gly-Gly-AspGlu-Phe motif in their catalytic domains, and c-di-GMP phosphodiesterases (PDEs), which degrade c-di-GMP (Cotter & Stibitz, 2007).…”