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

Didier Blaha (1, 2) , Safia Arous (1) , Camille Bleriot (1) , Corinne Dorel (1) , Marie-Andrée Mandrand-Berthelot (1) , Agnès Rodrigue (1)

1 MAP - Microbiologie, adaptation et pathogénie
2 LEM - Laboratoire d'Ecologie Microbienne - UMR 5557

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 promotereoperator 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.

Mots clés: Repressor proteins; Convergent promoters; Homeostasis; Cobalt; Nickel

Domaines: Biologie moléculaire; Biochimie [q-bio.BM]; Génomique, Transcriptomique et Protéomique [q-bio.GN]; Bactériologie

Didier Blaha, Safia Arous, Camille Bleriot, Corinne Dorel, Marie-Andrée Mandrand-Berthelot, et al.. 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. Biochimie, 2011, 93 (3), pp.434 - 439. ⟨10.1016/j.biochi.2010.10.016⟩. ⟨hal-01655156⟩