Escherichia coli ferric uptake regulator (Fur) can mediate regulation of a pseudomonad iron-regulated promoter

Abstract

Introduction of a Pseudomonas iron-regulated promoter lacZ fusion (SP1) and a Pseudomonas transcriptional factor into Escherichia coli allowed expression of the promoter in this heterologous host. Evaluation of this promoter in wild-type and fur mutants of E. coli, by measuring beta-galactosidase activity, indicated that E. coli Fur can regulate the Pseudomonas promoter in response to iron starvation. Gel retardation assays suggested that purified Fur protein could interact with the SP1 promoter upstream of the transcriptional start. DNase I footprinting analysis established that Fur protected a primary 58-bp region (-50 to -106 bp). These protein/DNA interactions correlate with the observed in vivo regulation of the SP1 promoter in E. coli and indicate that Fur can functionally regulate a Pseudomonas iron-regulated promoter.

Opening the Iron Box: Transcriptional Metalloregulation by the Fur Protein

“…In many cases, binding of such sequences by Fur EC (the Fur protein from E. coli) has been observed in in vitro or in vivo assays. For instance, some Pseudomonas genes that are regulated by Fur are retarded in band-shift gels and protected in footprinting assays with the protein from E. coli (71,74). Similarly, the fbpA gene of N. gonorrhoeae (encoding a periplasmic binding protein) is both regulated by Fur EC in in vivo and protected from DNase I in vitro (9,29).…”

Iron Starvation Conditions Upregulate Ehrlichia ruminantium Type IV Secretion System, tr1 Transcription Factor and map1 Genes Family through the Master Regulatory Protein ErxR

“…This sensing involves transcriptional control mediated by the transcriptional repressor, Fur (Escolar et al, 1998 ). But many organisms, including E. coli, Campylobacter jejuni , and Vibrio cholera , have been shown to use Fur to negatively regulate gene expression with increasing concentrations of iron (O'Sullivan et al, 1994 ; Palyada et al, 2004 ; Mey et al, 2005 ). For example, Fur activates sodB , an iron superoxide dismutase, under iron repletion.…”