Journal article
Orientation-dependent enhancement by H-NS of the type 1 fimbrial phase switch promoter in Escherichia coli
Phase variation of type 1 fimbriation in Escherichia coli is associated with the inversion of a 314-bp DNA element, positioned proximal to and upstream of fimA, which encodes the major type 1 fimbrial subunit. This DNA switch region contains a promoter that drives transcription of fimA only when the switch is in the ON orientation.
Using chromosomal and plasmid-borne lacZ reporter cassettes, we show here how the global regulator H-NS affects the activity of the fimA promoter. In phase-locked reporter cassettes the activity of the fimA promoter was found to be enhanced in a hns-positive background, but only when the switch was in the ON orientation.
Also, the number of fimbriae produced by a phase-locked ON strain was significantly higher in a hns-positive background. By means of competitive gel retardation and DNase I protection assays, H-NS binding to DNA segments adjacent to and within the phase switch region was demonstrated.
| Language: | English |
|---|---|
| Publisher: | Springer-Verlag |
| Year: | 1998 |
| Pages: | 336-344 |
| ISSN: | 14321874 and 00268925 |
| Types: | Journal article |
| DOI: | 10.1007/s004380050820 |
Bacterial Proteins Base Sequence Binding Sites DNA Primers DNA, Bacterial DNA-Binding Proteins Escherichia coli Expression enhancement Fimbriae Proteins Fimbriae, Bacterial Gene Expression Regulation, Bacterial Genes, Bacterial Genes, Switch H-NS H-NS binding H-NS protein, bacteria Key wordsfimA promoter Legacy Molecular Sequence Data Polymerase Chain Reaction Promoter Regions, Genetic Protein Binding Type 1 fimbriae fimbrillin
