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The role of FIS in trans activation of stable RNA operons of E. coli.
Author(s) -
Nilsson L.,
Vanet A.,
Vijgenboom E.,
Bosch L.
Publication year - 1990
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1990.tb08166.x
Subject(s) - operon , library science , escherichia coli , biology , genetics , gene , computer science
The thrU(tufB) operon of Escherichia coli is endowed with a cis‐acting region upstream of the promoter, designated UAS for Upstream Activator Sequence. A protein fraction has been isolated that binds specifically to DNA fragments of the UAS, thus forming three protein‐DNA complexes corresponding to three binding sites on the UAS. It stimulates in vitro transcription of the operon by facilitating the binding of the RNA polymerase to the promoter. All three protein‐DNA complexes contain one and the same protein. Dissociation constants for the three complexes have been determined, the lowest being in the sub‐nanomolar range. The protein also binds to the UAS of the tyrT operon and to the UAS upstream of the P1 promoter of the rrnB operon, suggesting that transcription of the three operons, if not of more stable RNA operons, is activated by a common trans activator. We demonstrate that the E.coli protein FIS (Factor for Inversion Stimulation) also binds to the UAS of the thrU(tufB) operon forming three protein‐DNA complexes. A burst of UAS‐ and FIS‐dependent promoter activity is observed after reinitiation of growth of stationary cultures in fresh medium.