The lrp gene and its role in type I fimbriation in Citrobacter rodentium

Mauriello, Emilia Maria Francesca (2006) The lrp gene and its role in type I fimbriation in Citrobacter rodentium. [Tesi di dottorato] (Inedito)

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Abstract

I studied the lrp gene of the murine pathogen C. rodentium and found that it encodes a product highly similar to members of the Lrp (leucine-responsive regulatory protein) family of transcriptional regulators, able to recognize leucine as an effector and to repress the expression of its own structural gene. In enterobacteria, Lrp is a global regulator of gene expression, as it controls a large variety of genes, including those coding for cell appendages and other potential virulence factors. Based on the well-established role of Lrp on the expression of pilus genes in Escherichia coli, I also studied the role of Lrp in controlling the formation of the type I pilus in C. rodentium. Type I pili, produced by the fim system, are virulence factors of uropathogens, involved in mediating bacterial adhesion to bladder epithelial cells. Yeast agglutination assays showed that Lrp is needed for type I pilus formation and real-time PCR experiments indicated that Lrp has a strong leucine-mediated effect on the expression of the fimAICDFGH operon. Mutant studies indicated that this positive action is exerted mainly through a positive control of Lrp on the phase variation mechanism that regulates fimAICDFGH expression. A quantitative analysis of its expression suggested that this operon may also be negatively regulated at the level of transcription. Finally, in vitro experiments showed that the C. rodentium type I pilus is involed in the internalization of this bacteria in uroepithelial cells, opening the possibility to use C. rodentium as an in vivo model system of human significant pathogens, as uropathogenic strains of E. coli.

Tipologia di documento:Tesi di dottorato
Settori scientifico-disciplinari MIUR:Area 05 Scienze biologiche > BIO/19 MICROBIOLOGIA GENERALE
Coordinatori della Scuola di dottorato:
Coordinatore del Corso di dottoratoe-mail (se nota)
De Felice, Maurilio
Tutor della Scuola di dottorato:
Tutor del Corso di dottoratoe-mail (se nota)
Ricca, Ezio
Stato del full text:Inedito
Data:2006
Numero di pagine:108
Istituzione:Università degli Studi di Napoli Federico II
Dipartimento o Struttura:Biologia Strutturale e Funzionale
Tipo di tesi:Dottorato
Stato dell'Eprint:Inedito
Denominazione del dottorato:Biologia Applicata
Ciclo di dottorato:XVIII
Numero di sistema:2462
Depositato il:18 Giugno 2008
Ultima modifica:04 Febbraio 2009 09:52

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