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 β-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.
|Original language||English (US)|
|Number of pages||6|
|Journal||FEMS Microbiology Letters|
|State||Published - Apr 15 1994|
Bibliographical noteFunding Information:
We are indebted to J.B. Neilands for the gift of purified Fur. The technical assistance of P. Higgins is appreciated. We also thank P. Ross for helpful discussions and T.R. Klaenhammer for supplying facilities for conducting the footprint-ing assays. This work was supported in part by contracts from the European Community (ECLAIR-AGRE-0019-C; BRIDGE BIOT-CT90-0166-C (EDB), BIOT-CT91-0293, BIOT-CT91-0283; and FLAIR AGRF-CT91-0049 (DTEE)).
- Iron-regulated promoter