The Escherichia coli metallo-regulator RcnR represses rcnA and rcnR transcription through binding on a shared operator site: Insights into regulatory specificity towards nickel and cobalt.
RcnA is an efflux pump responsible for Ni and Co detoxification in Escherichia coli. The expression of rcnA is induced by Ni and Co via the metallo-regulator RcnR. In the present work, the functioning of the promoter-operator region of rcnR and rcnA was investigated using primer extension and DNAse I footprinting experiments. We show that the promoters of rcnR and rcnA are convergent and that apo-RcnR binds on symmetrically located sequences in this intergenic region. Moreover, RcnR DNA binding is specifically modulated by one Ni or Co equivalent and not by other metals. In addition to rcnA, RcnR controls expression of its own gene in response to Ni and Co, but the two genes are differentially expressed.
UMR5240 Microbiologie Adaptation et Pathogénie, CNRS, Université de Lyon, Lyon, France.
Didier
D
Blaha
Safia
S
Arous
Camille
C
Blériot
Corinne
C
Dorel
Marie-Andrée
MA
Mandrand-Berthelot
Agnès
A
Rodrigue
D000595:Amino Acid Sequence; D001483:Base Sequence; D003035:Cobalt / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009532:Nickel / Q000378:metabolism*; D009875:Operator Regions, Genetic / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D029968:Escherichia coli Proteins; D008565:Membrane Proteins; C501738:RcnA protein, E coli; C558390:RcnR protein, E coli; D012097:Repressor Proteins; D003035:Cobalt; D009532:Nickel