Advertisement

Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Orientation-dependent enhancement by H-NS of the activity of the type 1 fimbrial phase switch promoter in Escherichia coli

Abstract

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.

This is a preview of subscription content, log in to check access.

Author information

Additional information

Received: 14 January 1998 / Accepted: 25 May 1998

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Schembri, M., Olsen, P. & Klemm, P. Orientation-dependent enhancement by H-NS of the activity of the type 1 fimbrial phase switch promoter in Escherichia coli . Mol Gen Genet 259, 336–344 (1998). https://doi.org/10.1007/s004380050820

Download citation

  • Key wordsfimA promoter
  • H-NS
  • H-NS binding
  • Expression enhancement
  • Type 1 fimbriae