![]() ![]() coli BL21(DE3), and insertion of the orfUs as well as usp in the constructed plasmid diminished the toxic effect, suggesting that co-expressed OrfUs masked the activity of Usp. We revealed that pET expression vector encoding Usp alone could not be maintained in E. The importance of H-N-H motif in nuclease activity of Usp was examined by site-directed mutagenesis study. The nuclease activity of the purified Usp was examined in vitro by using plasmid DNA as a substrate. coli BL21(DE3) cells together with 6× Histidine tagged OrfU1 (OrfU1-His) protein, and purified with affinity chromatography using Ni2+ chelating agarose. ![]() Recombinant Usp protein was expressed in E. coli, purify Usp and characterize its molecular activity. In this study, we try to over-express Usp in E. Although homology search revealed that Usp and OrfUs have a homology with nuclease-type bacteriocins, which possess H-N-H nuclease motif, and immunity proteins respectively, the molecular activity of these proteins was never investigated. The uropathogenic specific protein (Usp) and three OrfU proteins (OrfU1, OrfU2 and OrfU3) are encoded in the putative small pathogenicity island which is closely associated with Uropathogenic Escherichia coli. Our results indicate that usp may contribute to the causation of urinary tract infection and may be considered a major virulence determinant of uropathogenic E. coli host cell, whereas the 3 small proteins at the downstream of usp failed to show the effect. In challenge experiments using the mouse urinary tract infection model the vector possessing usp significantly enhanced the infectibility of the E. Furthermore, usp was frequently associated with all common serotypes of uropathogenic E. coli strains from healthy individuals (24%). coli strains (79.4% from cystitis, 93.4% from pyelonephritis and 88.8% from prostatitis) than with fecal E. The usp was significantly more often associated with uropathogenic E. coli strains possessing usp and/or orfU1 to 3 were constructed for evaluating the significance of these genes using an experimental pyelonephritis mouse model. coli strains isolated from the urine of 194, 76 and 107 subjects suffering from cystitis, pyelonephritis and prostatitis, respectively, and 50 isolates from the feces of healthy individuals were examined for genotypes and serotypes. ![]() In our current study we assessed the importance of the genes located in the putative virulence island in the pathogenesis of urinary tract infection using a mouse pyelonephritis model.Ī total of 427 E. We have observed that the island includes a gene consisting of a protein designated uropathogenic specific protein (usp) and 3 small open reading frames (orfU1-3). A putative virulence island commonly noted in the genome of uropathogenic Escherichia coli strains has recently been reported. ![]()
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