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Regulation of crp transcription by oscillation between distinct nucleoprotein complexes
Author(s) -
GonzálezGil Gardenia,
Kahmann Regine,
Muskhelishvili Georgi
Publication year - 1998
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 - 10.1093/emboj/17.10.2877
Subject(s) - biology , nucleoprotein , transcription (linguistics) , transcription factor , genetics , microbiology and biotechnology , computational biology , gene , linguistics , philosophy
FIS belongs to the group of small abundant DNA‐binding proteins of Escherichia coli . We recently demonstrated that, in vivo , FIS regulates the expression of several genes needed for catabolism of sugars and nucleic acids, a majority of which are also transcriptionally regulated by cAMP–cAMP‐receptor protein (CRP) complex. Here we provide evidence that FIS represses transcription of the crp gene both in vivo and in vitro . Employing crp promoter– lacZ fusions, we demonstrate that both FIS and cAMP–CRP are required to keep the crp promoter in a repressed state. We have identified in the crp promoter other transcription initiation sites which are located 73, 79 and 80 bp downstream from the previously mapped start site. Two CRP‐ and several FIS‐binding sites with different affinities are located in the crp promoter region, one of them overlapping the downstream transcription initiation sites. We show that initiation of transcription at the crp promoter is affected by the composition of nucleoprotein complexes resulting from the outcome of competition between proteins for overlapping binding sites. Our results suggest that the control of crp transcription is achieved by oscillation in the composition of these regulatory nucleoprotein complexes in response to the physiological state of the cell.