REPRESSION OF TRANSCRIPTION INITIATION BY ESCHERICHIA-COLI FNR PROTEIN - REPRESSION BY FNR CAN BE SIMPLE

Naturally occurring promoters that are repressed by the Escherichia co li FNR protein are complex. In this work, we have constructed a simple semi-synthetic promoter that is repressed by FNR binding to a single site that overlaps the promoter -35 element. Our results show that a s ingle site for FNR is sufficient for effective repression. This semi-s ynthetic promoter provides a simple tool for monitoring FNR binding to target sites in the absence of tis activation function. We have explo ited this to study FNR mutants that are defective in repressing the nd h promoter, a complex naturally occurring promoter that is repressed b y FNR. (C) 1998 Federation of European Microbiological Societies. Publ ished by Elsevier Science B.V. All rights reserved.