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Lrp–DNA complex stability determines the level of ON cells in type P fimbriae phase variation
Author(s) -
Graveline Richard,
Mourez Michaël,
Hancock Mark A.,
Martin Christine,
Boisclair Stéphanie,
Harel Josée
Publication year - 2011
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2011.07761.x
Subject(s) - phase variation , biology , repressor , fimbria , pilus , population , microbiology and biotechnology , escherichia coli , dna , regulator , genetics , gene , virulence , gene expression , demography , sociology
Summary F165 1 and the pyelonephritis‐associated pili (Pap) are two members of the type P family of adhesive factors that play a key role in the establishment of disease caused by extraintestinal Escherichia coli (ExPEC) strains. They are both under the control of an epigenetic and reversible switch that defines the number of fimbriated (ON) and afimbriated (OFF) cells within a clonal population. Our present study demonstrates that the high level of ON cells found during F165 1 phase variation is due to altered stability of the DNA complex formed by the leucine‐responsive regulatory protein (Lrp) at its repressor binding sites 1–3; after each cell cycle, complex formation is also modulated by the local regulator FooI (homologue to PapI) which promotes the transit of Lrp towards its activator binding sites 4–6. Furthermore, we identified two nucleotides (T490, G508) surrounding the Lrp binding site 1 that are critical to maintaining a high OFF to ON switch rate during F165 1 phase variation, as well as switching Pap fimbriae towards the OFF state.