The fim genes responsible for synthesis of type 1 fimbriae in Escherichia coli, cloning and genetic organization

Klemm, Per; Jørgensen, Birthe Jul; Die, Irma van; Ree, Han de; Bergmans, Hans

doi:10.1007/bf00330751

Cited by 181 publications

(125 citation statements)

References 30 publications

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“…Plasmids pPKL4, pPKL5, pPKL66, pPKL52, pPKL63, pPKL64, and pPKL65 containing all or part of the fim gene cluster have been described previously (11,14,16,17). Plasmid pPIL1 10-51 containing the total foc gene cluster and plasmid pPIL110-518 carrying a deletion in the focH gene have also been described previously (31,36 (4).…”

Section: Methodsmentioning

confidence: 99%

Reciprocal exchange of minor components of type 1 and F1C fimbriae results in hybrid organelles with changed receptor specificities

et al. 1994

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Type 1 and FlC fimbriae are surface organelles of Escherichia coli which mediate receptor-specific binding to different host surfaces. Such fimbriae are found on strains associated with urinary tract infections. The specific receptor binding of the fimbriae is due to the presence of receptor recognition proteins present in the organelles as minor structural elements. The organization of the fim and foc gene clusters encoding these fimbriae, as well as the structures of the organelles, are very similar, although the actual sequence homology of the structural elements is not remarkable; notably, the sequence identity between the minor components of the type 1 and FlC fimbriae is only 34 to 41%. Type 1 fimbriae mediate agglutination of guinea pig erythrocytes, whereas FlC fimbriae do not confer agglutination of any types of erythrocytes tested. However, FIC fimbriae mediate specific adhesion to epithelial cells in the collecting ducts of the human kidney as well as to cells of various cell lines. This report addresses the question of fimbrial promiscuity. Our data indicate that minor fimbrial structural elements can be exchanged between the two fimbrial systems, resulting in hybrid organelles with changed receptor specificity. This is the first study on reciprocal exchange of structural components from two different fimbrial systems.

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Section: Methodsmentioning

confidence: 99%

Reciprocal exchange of minor components of type 1 and F1C fimbriae results in hybrid organelles with changed receptor specificities

et al. 1994

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“…For quantification of P fimbrial expression, a gfp reporter was cloned in frame of the pap promoter [25]. The plasmid PKL4 carries the entire fim gene cluster from E. coli PC31 in the tet site of PBR322 [44] and was transformed into E. coli S1918, lacking the fim gene. …”

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confidence: 99%

Mechanism of pathogen‐specific TLR4 activation in the mucosa: Fimbriae, recognition receptors and adaptor protein selection

et al. 2006

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The mucosal host defence discriminates pathogens from commensals, and prevents infection while allowing the normal flora to persist. Paradoxically, Toll-like receptors (TLR) control the mucosal defence against pathogens, even though the TLR recognise conserved molecules like LPS, which are shared between pathogens and commensals. This study proposes a mechanism of pathogen-specific mucosal TLR4 activation, involving adhesive ligands and their host cell receptors. TLR4 signalling was activated in CD14-negative, LPS-unresponsive epithelial cells by P fimbriated, uropathogenic Escherichia coli but not by a mutant lacking fimbriae. Epithelial TLR4 signalling in vivo involved the glycosphingolipid receptors for P fimbriae and the adaptor proteins Toll/IL-1R (TIR) domain-containing adaptor inducing IFN-b (TRIF)/TRIF-related adaptor molecule (TRAM), but myeloid differentiation protein 88 (MyD88)/TIR domain-containing adaptor protein were not required for the epithelial response. Substituting the P fimbriae with type 1 fimbriae changed TLR4 signalling from the TRIF to the MyD88 adaptor pathway. In addition, the adaptor proteins and the fimbrial type were found to influence bacterial clearance. Trif -/-and Tram -/-mice remained infected with P fimbriated E. coli but cleared thetype 1 fimbriated strain, while Myd88 -/-mice became carriers of both the P and the type 1 fimbriated bacteria. Thus, TLR4 may be engaged specifically by pathogens, when the proper cell surface receptors are engaged by virulence ligands. IntroductionToll-like receptors (TLR) control the innate host defence at mucosal surfaces and yet commensals do not induce an inflammatory response at those sites. The relative inertia to the commensals is paradoxical, as the TLR recognise conserved pathogen-associated molecular patterns (PAMP), which are present on both pathogenic and commensal bacteria. Lipolysaccharide (LPS), flagellin, peptidoglycan or DNA may bind directly to the TLR but in addition, co-receptors are needed to enhance the TLR response to these conserved ligands [1][2][3]. Myeloid cells use CD14 and MD-2 as co-receptors for LPS in TLR4 signalling, and minute amounts of LPS may elicit a strong systemic inflammatory response [4,5]. However, the TLR response to pathogen attack at mucosal surfaces is controlled by different interactions. Epithelial cells must be protected from constant TLR activation by commensals and their PAMP, in order for mucosal integrity to be maintained. The epithelial cells thus lack co-receptors like CD14 [6][7][8][9][10][11], and in addition, commensals have been suggested to actively suppress epithelia responses through NF-jB [12,13]. Yet, mucosal pathogens evoke rapid TLR4-dependent responses at mucosal sites, suggesting that alternative ligands and receptors might be involved in mucosal TLR activation. Pathogens use adhesive surface ligands to break the inertia of the mucosal barrier [14][15][16]. The innate defence is activated as a direct result of these interactions and epithelial cells produce the first wave of me...

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“…The most common of the enterobacterial fimbriae, type 1, or mannose-specific (MS), fimbriae (11,13,14,23), are heteropolymers of four different subunits (28,44). Approximately 1,000 copies of the 17-kDa primary structural subunit, FimA (or PilA), are polymerized into a right-handed helical fibril also containing minor amounts of the FimF, FimG, and FimH subunits (20,24,27,32).…”

mentioning

confidence: 99%

“…The saccharide content of the four substrates was characterized by using concanavalin A, which reacts with terminal and internal mannosyl residues, and the Galanthus nivalis agglutinin, which recognizes only terminal Manal-3Man, Manal-6Man, and Manal2Man sequences (E. Y. Laboratories, San Mateo, Calif. containing the entire fim gene cluster from E. coli K-12 strain PC31, has been described previously (28). pPKL114 is a recombinant plasmid derived from pPKL4 but with a translational stop-linker inserted into the KpnI site in the fimH gene.…”

mentioning

confidence: 99%

FimH family of type 1 fimbrial adhesins: functional heterogeneity due to minor sequence variations among fimH genes

et al. 1994

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We recently reported that the type 1-fimbriated Escherichia coli strains CSH-50 and HB101(pPKIA), both K-12 derivatives, have different patterns of adhesion to yeast mannan, human plasma fibronectin, and fibronectin derivatives, suggesting functional heterogeneity of type 1 fimbriae. In this report, we provide evidence that this functional heterogeneity is due to variations in the fimH genes. We also investigated functional heterogeneity among clinical isolates and whether variation infimH genes accounts for differences in receptor specificity. Twelve isolates obtained from human urine were tested for their ability to adhere to mannan, fibronectin, periodate-treated fibronectin, and a synthetic peptide copying the 30 amino-terminal residues of fibronectin. CSH-50 and HB101(pPKLA) were tested for comparison. Selected isolates were also tested for adhesion to purified fragments spanning the entire fibronectin molecule. Three distinct functional classes, designated M, MF, and MFP, were observed. The fimH genes were amplified by PCR from chromosomal DNA obtained from representative Strains and expressed in a Afim strain (AAEC191A) transformed with a recombinant plasmid containing the entire fim gene cluster but with a translational stop-linker inserted into the fimH gene (pPKL114). Cloned fimH genes conferred on AAEC191A(pPKL114) receptor specificities mimicking those of the parent strains from which the fimH genes were obtained, demonstrating that the FimH subunits are responsible for the functional heterogeneity. RepresentativefimH genes were sequenced, and the deduced amino acid sequences were compared with the previously published FimH sequence. Allelic variants exhibiting >98% homology and encoding proteins differing by as little as a single amino acid substitution confer distinct adhesive phenotypes. This unexpected adhesive diversity within the FimH family broadens the scope of potential receptors for enterobacterial adhesion and may lead to a fundamental change in our understanding of the role(s) that type 1 fimbriae may play in enterobacterial ecology or pathogenesis.

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The fim genes responsible for synthesis of type 1 fimbriae in Escherichia coli, cloning and genetic organization

Cited by 181 publications

References 30 publications

Reciprocal exchange of minor components of type 1 and F1C fimbriae results in hybrid organelles with changed receptor specificities

Reciprocal exchange of minor components of type 1 and F1C fimbriae results in hybrid organelles with changed receptor specificities

Mechanism of pathogen‐specific TLR4 activation in the mucosa: Fimbriae, recognition receptors and adaptor protein selection

FimH family of type 1 fimbrial adhesins: functional heterogeneity due to minor sequence variations among fimH genes

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