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Regulatory cross‐talk between adhesin operons in Escherichia coli : inhibition of type 1 fimbriae expression by the PapB protein
Author(s) -
Xia Yan,
Gally David,
ForsmanSemb Kristina,
Uhlin Bernt Eric
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.7.1450
Subject(s) - operon , biology , fimbria , bacterial adhesin , lac operon , escherichia coli , gene , genetics , microbiology and biotechnology
Pathogenic Escherichia coli often carry determinants for several different adhesins. We show a direct communication between two adhesin gene clusters in uropathogenic E.coli : type 1 fimbriae ( fim ) and pyelonephritis‐associated pili ( pap ). A regulator of pap , PapB, is a key factor in this cross‐talk. FimB recombinase turns on type 1 fimbrial expression, and PapB inhibited phase transition by FimB in both off‐to‐on and on‐to‐off directions. On‐to‐off switching requiring FimE was increased by PapB. By analysis of FimB– and FimE–LacZ translational fusions it was concluded that the increase in on‐to‐off transition rates was via an increase in FimE expression. Inhibition of FimB‐promoted switching was via a different mechanism: PapB inhibited FimB‐promoted in vitro recombination, indicating that FimB activity was blocked at the fim switch. In vitro analyses showed that PapB bound to several DNA regions of the type 1 fimbrial operon, including the fim switch region. These data show that Pap expression turns off type 1 fimbriae expression in the same cell. Such cross‐talk between adhesin gene clusters may bring about appropriate expression at the single cell level.