The transcription of csrB is regulated by SirA .
SirA regulates csrC In both Salmonella and E. coli , SirA directly regulates csrB .
To test the hypothesis that csrC is directly regulated by SirA , in-vitro gel mobility-shift assays were performed as previously described for csrB .
SirA of Salmonella both control the csr system by directly binding the csrB gene .
These two reports suggest that in contrast to csrB , the regulation of csrC by SirA may be indirect .
No further increase in PefA expression was apparent in a sirA csrB csrC DfimAICDHF mutant ( TS133 ) ( Figure 2C ) , thus the lack of SirA or inactivation of the SirA-regulated genes csrB and csrC produced similar effects on PefA expression .
No further increase in PefA expression was apparent in a sirA csrB csrC DfimAICDHF mutant ( TS133 ) ( Figure 2C ) , thus the lack of SirA or inactivation of the SirA-regulated genes csrB and csrC produced similar effects on PefA expression .
In S. typhimurium , SirA is a positive regulator of csrB .
In E. coli , SirA is a positive regulator of csrB .