PubMed:12951338 JSONTXT

{"project":"FSU-PRGE","denotations":[{"id":"T1","span":{"begin":58,"end":77},"obj":"protein"},{"id":"T2","span":{"begin":264,"end":282},"obj":"protein"},{"id":"T3","span":{"begin":352,"end":371},"obj":"protein"},{"id":"T4","span":{"begin":400,"end":418},"obj":"protein"},{"id":"T5","span":{"begin":520,"end":524},"obj":"protein"},{"id":"T6","span":{"begin":700,"end":719},"obj":"protein"},{"id":"T7","span":{"begin":744,"end":748},"obj":"protein"},{"id":"T8","span":{"begin":750,"end":754},"obj":"protein"},{"id":"T9","span":{"begin":756,"end":760},"obj":"protein"},{"id":"T10","span":{"begin":762,"end":766},"obj":"protein"},{"id":"T11","span":{"begin":768,"end":772},"obj":"protein"},{"id":"T12","span":{"begin":774,"end":778},"obj":"protein"},{"id":"T13","span":{"begin":780,"end":784},"obj":"protein"},{"id":"T14","span":{"begin":786,"end":790},"obj":"protein"},{"id":"T15","span":{"begin":792,"end":796},"obj":"protein"},{"id":"T16","span":{"begin":798,"end":802},"obj":"protein"},{"id":"T17","span":{"begin":804,"end":808},"obj":"protein"},{"id":"T18","span":{"begin":810,"end":814},"obj":"protein"},{"id":"T19","span":{"begin":819,"end":823},"obj":"protein"},{"id":"T20","span":{"begin":899,"end":903},"obj":"protein"},{"id":"T21","span":{"begin":905,"end":909},"obj":"protein"},{"id":"T22","span":{"begin":911,"end":915},"obj":"protein"},{"id":"T23","span":{"begin":920,"end":924},"obj":"protein"},{"id":"T24","span":{"begin":962,"end":966},"obj":"protein"},{"id":"T25","span":{"begin":972,"end":976},"obj":"protein"},{"id":"T26","span":{"begin":1068,"end":1072},"obj":"protein"},{"id":"T27","span":{"begin":1077,"end":1083},"obj":"protein"},{"id":"T28","span":{"begin":1088,"end":1092},"obj":"protein"},{"id":"T29","span":{"begin":1098,"end":1103},"obj":"protein"},{"id":"T30","span":{"begin":1108,"end":1112},"obj":"protein"},{"id":"T31","span":{"begin":1122,"end":1126},"obj":"protein"},{"id":"T32","span":{"begin":1132,"end":1136},"obj":"protein"},{"id":"T33","span":{"begin":1224,"end":1228},"obj":"protein"},{"id":"T34","span":{"begin":1286,"end":1290},"obj":"protein"},{"id":"T35","span":{"begin":1309,"end":1313},"obj":"protein"},{"id":"T36","span":{"begin":1343,"end":1347},"obj":"protein"}],"text":"Beta-lactam resistance modulated by the overexpression of response regulators of two-component signal transduction systems in Escherichia coli.\nOBJECTIVES: In Escherichia coli, there are 32 open reading frames assumed, on the basis of sequence similarities, to be response regulator genes of two-component signal transduction systems. We cloned all 32 response regulators and examined whether or not response regulator-overexpressing cells confer resistance to beta-lactam antibiotics in E. coli.\nMETHODS: E. coli KAM3 (acrB), a drug-hypersusceptible mutant, was used as a host strain for the overproduction of response regulators. MICs were determined by the agar dilution method.\nRESULTS: Thirteen response regulators out of 32 genes, namely baeR, cheY, cpxR, creB, evgA, fimZ, narL, ompR, rcsB, rstA, yedW, yehT and dcuR, conferred increased beta-lactam resistance. Among them, overexpression of baeR, evgA, rcsB and dcuR conferred high-level resistance. The baeR- and evgA-mediated resistance is due to up-regulation of the expression of multidrug exporter genes, acrD and mdtABC for baeR, and yhiUV for evgA, because baeR- and evgA-mediated resistance was completely absent in strains lacking these exporter genes. The fimZ-mediated cefalothin resistance is due to the chromosomal ampC gene, because the ampC deletion strain did not show fimZ-mediated resistance.\nCONCLUSIONS: Two-component signal transduction systems contribute to beta-lactam resistance in E. coli. Multidrug exporters play roles in two-component signal transduction system-mediated beta-lactam resistance."}