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Transcriptional Regulation of the assT-dsbL-dsbI Gene Cluster in Salmonella enterica Serovar Typhi IMSS-1 Depends on LeuO, H-NS, and Specific Growth Conditions
- Gallego-HernÃ¡ndez, A. L., HernÃ¡ndez-Lucas, I., De la Cruz, M. A., Olvera, L., Morett, E., Medina-Aparicio, L., RamÃrez-Trujillo, J. A., VÃ¡zquez, A., FernÃ¡ndez-Mora, M., Calva, E.
- Journal of bacteriology 2012 v.194 no.9 pp. 2254-2264
- Salmonella enterica subsp. enterica serovar Typhi, disulfide bonds, operon, regulatory proteins, transcription (genetics)
- The assT gene encodes an arylsulfate sulfotransferase, an enzyme that catalyzes sulfuryl transfer from phenolic sulfate to a phenolic acceptor. In Salmonella enterica serovar Typhi IMSS-1, the assT gene is located upstream of the dsbL and dsbI genes, which are involved in a disulfide bond formation required for its activation. The assT-dsbL-dsbI gene cluster forms an operon transcribed by a LeuO-dependent promoter, in rich medium A (MA). Interestingly, in the absence of cloned leuO and in a ÎleuO background, two transcription start sites were detected for assT and two for dsbL-dsbI in minimal medium. The H-NS nucleoid protein repressed the expression of the assT-dsbL-dsbI LeuO-dependent operon, as well as of the assT transcriptional units. Thus, the expression of the assT-dsbL-dsbI gene cluster depends on the global regulatory proteins LeuO and H-NS, as well as on specific growth conditions.