ThesctRofSalmonella entericaserova Typhimurium encoding a homologue of MerR protein is involved in the copper-responsive regulation ofcuiD

We have identified the cuiD gene in Salmonella enterica serova Typhimurium that codes for a putative multicopper oxidase. Expression of cuiD is induced by copper ion and its promoter/operator has sequence similarity to the promoters controlled by the transcriptional regulators of the MerR family. We also identified and isolated a gene from S. enterica serova Typhimurium that encodes a 138-amino acid residue protein, sctR, a new member of the MerR family of transcriptional regulators. Transposon-insertional disruption of sctR shows sensitivity to copper ion and no response of cuiD expression. Copper-responsive induction and copper tolerance were restored by providing sctR in trans, suggesting that SctR plays an important role in intracellular copper detoxification.