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Differential temperature modulation by H-NS of thefimBandfimErecombinase genes which control the orientation of the type 1 fimbrial phase switch
- Source :
- FEMS Microbiology Letters. 162:17-23
- Publication Year :
- 1998
- Publisher :
- Oxford University Press (OUP), 1998.
-
Abstract
- Phase variation of type 1 fimbriation in Escherichia coli is associated with the inversion of a 314-bp DNA element. This DNA switch directs transcription of fimA, encoding the major type 1 fimbrial subunit, in the on orientation but not in the off orientation. Inversion of the DNA element requires either FimB (confers both on and off orientations) or FimE (confers off orientation). Here we show, by chromosomally located fimB- and fimE-lacZ cassettes in isogenic strain sets differing only in the hns locus, how the global regulator H-NS affects the expression of type 1 fimbriae. H-NS was found to downregulate fimB and fimE in a temperature-dependent manner which affected the genes inversely at 30 degrees C and 37 degrees C. By gel-retardation assays H-NS binding was demonstrated to the regions containing the fimB promoter and the fimE promoter, respectively. In vitro recombination analysis suggested no direct involvement of H-NS in the inversion of the phase switch. Rather than directly affecting the switching process per se, it appeared that the orientation of this element was affected by the differential temperature modulation of H-NS of the fimB and fimE genes. Taken together the results suggest that H-NS modulates expression of type 1 fimbriae in a way which seems to favor a fimbriate state at the mammalian body temperature.
- Subjects :
- DNA, Bacterial
Fimbria
DNA, Recombinant
Biology
medicine.disease_cause
Microbiology
Recombinases
chemistry.chemical_compound
Bacterial Proteins
Transcription (biology)
Escherichia coli
Genetics
Recombinase
medicine
Promoter Regions, Genetic
Molecular Biology
Gene
Phase variation
Integrases
Escherichia coli Proteins
Temperature
Gene Expression Regulation, Bacterial
DNA-Binding Proteins
chemistry
Genes, Bacterial
Fimbriae, Bacterial
DNA Nucleotidyltransferases
In vitro recombination
DNA
Subjects
Details
- ISSN :
- 15746968 and 03781097
- Volume :
- 162
- Database :
- OpenAIRE
- Journal :
- FEMS Microbiology Letters
- Accession number :
- edsair.doi.dedup.....ee1c86597f596e5048a7c2bf7ffdb7fb