Mutations in E coli cistrons affecting adhesion to human cells do not abolish Pap pili fiber formation.

Abstract

A chromosomal DNA fragment which mediates Pap (pili associated with pyelonephritis) pili formation, mannose‐resistant hemagglutination (MRHA) and binding to uroepithelial cells has been isolated from the uropathogenic Escherichia coli clinical isolate J96, and genetically studied. Analysis of polypeptides expressed by the Pap DNA led to detection of a number of polypeptides ranging in mol. wt. from 13 000 to 81 000 daltons. The gene order and transcriptional orientation for four of the corresponding cistrons was: 13 000 (papB) 19 500 (papA, structural gene for the Pap pilus subunit), 81 000 (papC) and 28 500 (papD). Analyses of a lacZ‐ papA gene fusion located a promoter upstream from papA within the cloned DNA. Transposon Tn5 insertions in any of these four cistrons decreased or eliminated Pap pili formation. A number of transposon Tn5 mutations were identified in a region distal to papD that expressed normal levels of the papA protein on the cell surface in the form of recognizable pili structures but did not agglutinate human erythrocytes or adhere to uroepithelial cells. This region expressed polypeptides of 15 000, 24 000, 26 000 and 35 000 daltons. This finding shows that Pap pili formation and binding properties can be genetically dissociated.

Demonstration of regulatory cross-talk between P fimbriae and type 1 fimbriae in uropathogenic Escherichia coli

“…Functional expression of the Pap-related adhesin gene clusters was assessed by MRHA of human RBCs, a measure of P-fimbrial binding capacity (Norgren et al, 1984). Analysis of variance showed that the mean level of MRHA was significantly higher in the cystitis group compared to the asymptomatic group (P=0?037).…”

“…Despite selective bias of the presence of at least one P-related cluster (normally asymptomatic isolates tend not to carry P-related clusters), analysis of association using the chi square test revealed that the pyelonephritis isolates were more likely to possess multiple P fimbrial clusters than the asymptomatic isolates (P=0?009). The cystitis isolates also differed from the pyelonephritis isolates, since they were shown to be more likely to carry only one P fimbrial cluster (P=0?056).Functional expression of the Pap-related adhesin gene clusters was assessed by MRHA of human RBCs, a measure of P-fimbrial binding capacity (Norgren et al, 1984). Analysis of variance showed that the mean level of MRHA was significantly higher in the cystitis group compared to the asymptomatic group (P=0?037).…”

Protein secretion and the pathogenesis of bacterial infections

“…Pap (type I) pili are assembled from six pilins, all of which are encoded by a single large operon (Soto and Hultgren 1999). To identify the position of pilins within the pilus, wild-type E. coli and mutants lacking single pilin genes were analyzed by electron microscopy and immuno-gold labeling (Norgren et al 1984;Baga et al 1987;Lindberg et al 1987;Kuehn et al 1992;Jacob-Dubuisson et al 1993). PapG pilin (G in Fig.…”

“…The fibrillum, which consists mostly of PapE subunits, is attached to the pilus rod via a second adapter protein, PapK ). PapA is the major pilin subunit and assembles to form the pilus rod (Normark et al 1983;Norgren et al 1984). PapH terminates the polymerization of PapA and is presumably positioned at the pilus base within the plane of the outer membrane bilayer (Baga et al 1987).…”

Cloning and genetic organization of the gene cluster encoding F71fimbriae of a uropathogenicEscherichia coliand comparison with the F72gene cluster

“…For the Pap fimbrial gene duster, a non-polar mutation in the fimbrial subunit did not result inloss of MRHA [18,19]. JA221 cells harboring pPILl10-751, that expresses all proteins of the F71 fimbrial gene cluster except the fimbrial subunit (Fig.…”