The Escherichia coli regulator of sigma 70 protein, Rsd, can up-regulate some stress-dependent promoters by sequestering sigma 70.
The Escherichia coli Rsd protein forms complexes with the RNA polymerase sigma(70) factor, but its biological role is not understood. Transcriptome analysis shows that overexpression of Rsd causes increased expression from some promoters whose expression depends on the alternative sigma(38) factor, and this was confirmed by experiments with lac fusions at selected promoters. The LP18 substitution in Rsd increases the Rsd-dependent stimulation of these promoter-lac fusions. Analysis with a bacterial two-hybrid system shows that the LP18 substitution in Rsd increases its interaction with sigma(70). Our experiments support a model in which the role of Rsd is primarily to sequester sigma(70), thereby increasing the levels of RNA polymerase containing the alternative sigma(38) factor.
Mitchell
Jennie E
JE
School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom.
Oshima
Taku
T
Piper
Sarah E
SE
Webster
Christine L
CL
Westblade
Lars F
LF
Karimova
Gouzel
G
Ladant
Daniel
D
Kolb
Annie
A
Hobman
Jon L
JL
Busby
Stephen J W
SJ
Lee
David J
DJ
D019943:Amino Acid Substitution; D019677:Artificial Gene Fusion; D001426:Bacterial Proteins / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D007763:Lac Operon; D020125:Mutation, Missense; D020411:Oligonucleotide Array Sequence Analysis; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012808:Sigma Factor / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D015854:Up-Regulation; D001616:beta-Galactosidase / Q000096:biosynthesis
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; C112239:Rsd protein, E coli; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases; D001616:beta-Galactosidase