Identification of Bacterial Factors Involved in Type 1 Fimbria Expression using an Escherichia coli K12 Proteome Chip

Abstract

Type 1 fimbriae are filamentous structures on Escherichia coli. These structures are important adherence factors. Because binding to the host cells is the first step of infection, type 1 fimbria is an important virulence factor of pathogenic E. coli. Expression of type 1 fimbria is regulated by a phase variation in which each individual bacterium can alternate between fimbriated (phase-ON) and nonfimbriated (phase-OFF) states. The phase variation is regulated by the flipping of the 314-bp fimS fragment, which contains the promoter driving the expression of the genes required for the synthesis of type 1 fimbria. Thus, the bacterial proteins able to interact with fimS are likely to be involved in regulating the expression of type 1 fimbria. To identify novel type 1 fimbria-regulating factors, we used an E. coli K12 proteome chip to screen for the bacterial factors able to interact with a 602-bp DNA fragment containing fimS and its adjacent regions. The Spr protein was identified by the proteome chip-based screening and further confirmed to be able to interact with fimS by electrophoretic mobility shift assay. Deletion of spr in the neonatal meningitis E. coli strain RS218 significantly increased the ratio of the bacterial colonies that contained the type 1 fimbria phase-ON cells on agar plates. In addition, Spr interfered with the interactions of fimS with the site-specific recombinases, FimB and FimE, which are responsible for mediating the flipping of fimS. These results suggest that Spr is involved in the regulation of type 1 fimbria expression through direct interaction with the invertible element fimS. These findings facilitate our understanding of the regulation of type 1 fimbria. Molecular &

Population structure and pangenome analysis of Enterobacter bugandensis uncover the presence ofblaCTX-M-55,blaNDM-5andblaIMI-1, along with sophisticated iron acquisition strategies

“…GI1 has 4,305 bp, encompassing seven genes, mainly of unknown function, while GI2 has 9,148 bp, comprising ten genes related to type 1 fimbrial assembly. Type 1 fimbriae are filamentous surface organelles that mediate bacterial adherence to biotic and abiotic surfaces [25]. Interestingly, E. bugandensis UENF-21GII possesses several other genes related to type 1 fimbrial assembly along its core and accessory genomes, suggesting that this unique horizontally-acquired fimbrial operon might play specific roles in this strain.…”

Peptidoglycan Endopeptidase Spr of Uropathogenic Escherichia coli Contributes to Kidney Infections and Competitive Fitness During Bladder Colonization

“…Type-1 fimbia is a well-known adherence factor of UPEC to bind to bladder epithelial cells during UTIs ( Kaper et al, 2004 ). It has been reported that in a neonatal meningitides E. coli strain RS218 spr deletion increases the ratio of the colonies containing Type 1 fimbria phase-ON cells when they are grown on agar plates, and that the crosstalk between the expression of Type 1 fimbria and flagella has been shown in E. coli strains ( Barnich et al, 2003 ; Lane et al, 2007b ; Chen et al, 2014 ). However, Spr deficiency may not affect the expression of Type 1 fimbria in the UPEC strain UTI89, because WT-UTI89 and ∆ spr -UTI89 showed similar levels of Type 1 fimbria phase-ON bacteria in the culture ( Supplementary Figure S5 ).…”

Systematic protein interactome analysis of glycosaminoglycans revealed YcbS as a novel bacterial virulence factor

“…The ycbS -lacking E. coli mutant was obtained from the Keio collection 41 . To complement the Keio ycbS mutants, the plasmid pCA24N–ycbS harbouring ycbS was obtained from the ASKA clone library 42 and used to transform the ycbS mutant, as previously described 47 .…”