A role for the leucine-responsive regulatory protein and integration host factor in the regulation of the Salmonella plasmid virulence (spv ) locus in Salmonella typhimurium

1999 ◽  
Vol 34 (1) ◽  
pp. 134-145 ◽  
Author(s):  
David G. Marshall ◽  
Brian J. Sheehan ◽  
Charles J. Dorman
Keyword(s):  
Salmonella Typhimurium ◽  
Regulatory Protein ◽  
Integration Host Factor ◽  
Host Factor

scholarly journals Activation from a Distance: Roles of Lrp and Integration Host Factor in Transcriptional Activation ofgltBDF

2001 ◽  
Vol 183 (13) ◽  
pp. 3910-3918 ◽  
Author(s):  
Ligi Paul ◽  
Robert M. Blumenthal ◽  
Rowena G. Matthews
Keyword(s):  
Binding Site ◽  
Transcriptional Activation ◽  
Core Promoter ◽  
Regulatory Protein ◽  
Glutamate Synthase ◽  
Promoter Sequence ◽  
Integration Host Factor ◽  
Host Factor ◽  
Upstream Region ◽  
Mobility Shift

ABSTRACT The leucine-responsive regulatory protein (Lrp) binds to three sites centered 252, 216, and 152 bp upstream of the transcription start site of the Escherichia coli glutamate synthase operon (gltBDF) and activates transcription. Activators of ς70-dependent promoters usually bind closer to the −35 hexamer of the core promoter sequence. To study the mechanism by which Lrp-dependent activation occurs over this relatively large distance, the gltBDF upstream region was sequentially replaced with corresponding portions from the well-characterized ς70-dependent promoter lacZYAp. Theglt-lac promoter hybrids were placed upstream oflacZ, allowing transcriptional activity to be monitored via β-galactosidase assays. Even replacing all gltBDFsequences downstream of and including the −35 hexamer did not eliminate Lrp-dependent activation of transcription. When a 91-bp region between the −35 hexamer and the proximal Lrp binding site (−48 to −128) was replaced with heterologous DNA of the same length, transcription was reduced nearly 40-fold. Based on the presence of a consensus binding sequence, this region seemed likely to be a binding site for integration host factor (IHF). Experiments to study the effects of a himD mutant on expression of agltB::lacZ transcriptional fusion, gel mobility shift analyses, and DNA footprinting assays were used to confirm the direct participation of IHF in gltBDF promoter regulation. Based on these results, we suggest that IHF plays a crucial architectural role, bringing the distant Lrp complex in close proximity to the promoter-bound RNA polymerase.

Integration host factor facilitates repression of the put operon in Salmonella typhimurium

Gene ◽  
1992 ◽  
Vol 118 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Kathryn O'Brien ◽  
Gregory Deno ◽  
Paula Ostrovsky de Spicer ◽  
Jeffrey F. Gardner ◽  
Stanley R. Maloy
Keyword(s):  
Salmonella Typhimurium ◽  
Integration Host Factor ◽  
Host Factor

Integration Host Factor (IHF) modulates the expression of the pyrimidine-specific promoter of the carAB operons of Escherichia coli K12 and Salmonella typhimurium LT2

1993 ◽  
Vol 237-237 (1-2) ◽  
pp. 273-286 ◽  
Author(s):  
Daniel Charlier ◽  
Martine Roovers ◽  
Daniel Gigot ◽  
Nadine Huysveld ◽  
André Piérard ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhimurium ◽  
Integration Host Factor ◽  
Host Factor ◽  
Escherichia Coli K12
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