It contained a part of the pef operon and the srg ( SdiA-regulated gene ) region , including srgA , a homolog of dsbA ( disulfide bond isomerase ) ; srgB ; rck ( resistance to complement killing ) ; and srgC , a homolog of the AraC family of transcriptional regulators .
The genes , including the pef operon , PSLT026 , PSLT025 , PSLT024 , rsk , repA2 , srg ( srgA and srgB , SdiA-regulated gene ) , rck and srgC , are located in a region of about 11-kb in pSTLT2 ( McClelland et al. , 2001 ) ; however , in pOU1113 , the genes as well as the nucleotide sequences in this region ( 12 255 -- 23 104 bp ) were very different , occupied instead by a unique segment .
Moreover as rck is also regulated by an unidentified SdiA-independent system at 42 , it is conceivable that Rck invasion mechanism is not restricted to the gastrointestinal tract .
Moreover as rck is also regulated by an unidentified SdiA-independent system at 37 ° , it is conceivable that Rck invasion mechanism is not restricted to the gastrointestinal tract .
rck operons are controlled by the Salmonella N-Acyl homoserine lactone receptor SdiA
rck operons are controlled by the Salmonella N-Acyl homoserine lactone receptor SdiA
To decipher the regulation of rck by SdiA , we first confirmed the operon organization of the pefI-srgC locus .
These results demonstrate that the transcriptional regulation of rck by SdiA previously observed also modulates Rck protein expression .
We thus decided to further characterize the mechanism of transcriptional regulation of rck by SdiA .
Different rck regulation by SdiA between S. Typhimurium is due to differences in the promoter region of the pefI-srgC operon As mentioned in the Introduction part , the pefI-srgC operon is present in its complete form only on the virulence plasmid of Enteritidis .
Different rck regulation by SdiA between S. Typhimurium is due to differences in the promoter region of the pefI-srgC operon As mentioned in the Introduction part , the pefI-srgC operon is present in its complete form only on the virulence plasmid of the two broad-host-range serotypes Typhimu-rium .
Different rck regulation by SdiA between S. Enteritidis is due to differences in the promoter region of the pefI-srgC operon As mentioned in the Introduction part , the pefI-srgC operon is present in its complete form only on the virulence plasmid of Enteritidis .
Different rck regulation by SdiA between S. Enteritidis is due to differences in the promoter region of the pefI-srgC operon As mentioned in the Introduction part , the pefI-srgC operon is present in its complete form only on the virulence plasmid of the two broad-host-range serotypes Typhimu-rium .
The PefIP2 promoters are absent in S. Enteritidis , suggesting a mechanism of regulation of rck expression by SdiA different between these two sero-types .
The PefIP1 promoters are absent in S. Enteritidis , suggesting a mechanism of regulation of rck expression by SdiA different between these two sero-types .
This result demonstrates that the regulation of rck expression by SdiA is different between these two serotypes .
H-NS negatively regulates Rck expression at 37 °C As our results were not supporting an involvement of SdiA in the transcriptional regulation of rck at low-temperature , we searched for another regulatory mechani .
In this study , we first confirmed that the transcriptional regulation of rck by SdiA resulted in an increase of Rck protein expression .
Upon detecting AHLs produced by other species of bacteria , SdiA in Salmonella activates expression of two srg ( SdiA-regulated gene ) loci , the rck operon that encodes seven genes and the srgE gene ( 1 , 61 ) .
AI-1 Signaling in Salmonella Upon detecting AHLs produced by other species of bacteria , SdiA in Salmonella activates expression of two srg ( SdiA-regulated gene ) loci , the rck operon that encodes seven genes and the srgE gene ( 19 , 35 ) .
Abed et al. also showed that the promoter region of the rck operon , located on the S. enterica serovar Typhimurium ATCC 14018 plasmid , is regulated by the SdiA protein in the presence of AHL .