Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0034186 (pyelonephritis)
 6,144 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We previously showed, using a single-copy papBAp-lac fusion (previously designated papBA-lac), that pyelonephritis-associated pili (pap) pilin gene transcription is subject to both phase variation and thermoregulatory control mechanisms (L. B. Blyn, B. A. Braaten, C. A. White-Ziegler, D. H. Rolfson, and D. A. Low, EMBO J. 8:613-620, 1989). At 37 degrees C, Escherichia coli strains carrying the papBAp-lac fusion displayed both Lac+ and Lac- colony phenotypes. In contrast, at 23 degrees C, colonies displayed a uniform Lac- phenotype, suggesting that pilin was not transcribed at this temperature. In this study, a strain carrying the papBAp-lac fusion was subjected to mini-Tn10 (mTn10) mutagenesis to isolate mutants that could initiate transcription of pilin at the nonpermissive temperature. Two classes of thermoregulatory mutants were identified in which the mTn10 mutation was linked to the mutant phenotype. Class I mutants displayed a phase variation phenotype at both 37 degrees C and 23 degrees C, whereas class II mutants displayed a uniform Lac+ colony phenotype at both temperatures. Preliminary analysis of these mutants showed that the mTn10 insertions in the class I mutants were chromosomally located, whereas the mTn10 insertions in the class II mutants were located within the papBAp-lac fusion phage. Southern blot analysis of the class I mutants demonstrated that mTn10 was present in the same 5.9-kilobase SalI DNA fragment in each mutant. Two of the class I mTn10 mutations were mapped to approximately 23.4 min on the E. coli K-12 chromosome. The locus defined by the class I mTn10 mutations was designated tcp, for thermoregulatory control of pap. Analysis of phase transition rates of the class I mutants showed that the phase-off (Lac-)----phase-on (Lac+) transition rates were higher than those observed with the nonmutant E. coli strain.
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PMID:Identification of an Escherichia coli genetic locus involved in thermoregulation of the pap operon. 215 3

The regulation of pyelonephritis-associated pili (pap) pilin gene transcription has been examined using two operons (pap-17 and pap-21) isolated from the pyelonephritogenic Escherichia coli strain C1212. DNA sequence analysis and E. coli minicell analysis were used to map two genes (papB and papI) within the pilin regulatory regions of both pap-17 and pap-21, and the protein products of these genes were identified. Pilin transcription, initiated at the papBA promoter, was monitored by constructing single copy operon fusions with lacZYA in E. coli K-12. Inoculation of E. coli (pap'-lac) strains onto solid M9 minimal medium containing glycerol and the Lac indicator X-gal (M9-Glycerol) yielded both Lac+ and Lac- colony phenotypes. The Lac+ ("phase on') and Lac- ("phase off') phenotypes were heritable since reinoculation of M9-Glycerol with bacteria picked from Lac+ colonies gave rise to a much higher fraction of Lac+ colonies than reinoculation of M9-Glycerol with bacteria picked from Lac- colonies. Measurement of phase transition rates for E. coli (pap17'-lac) inoculated onto M9-Glycerol showed that the Lac(-)----Lac+ transition frequency (1.57 X 10(-4)/cell/generation) was reduced 35-fold when cells were inoculated onto minimal medium containing glucose (M9-Glucose). However, the Lac+----Lac-transition frequency obtained using M9-Glycerol (2.60 X 10(-2)/cell/generation) was 1.4-fold lower compared to results obtained with M9-Glucose. In contrast, lowering the incubation temperature of E. coli (pap17'-lac) cultures from 37 degrees C to 23 degrees C caused all cells to shift to the Lac- state.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Phase-variation of pyelonephritis-associated pili in Escherichia coli: evidence for transcriptional regulation. 265 60