While csgD is positively regulated by RpoS via MlrA , it itself stimulates the production of curli fimbriae through the transcriptional activation of the csgBAC operon .
To further distinguish between the contribution of RpoS to csgD morphotype expression , we compared the phenotype of an arcZ mutant with an rpoS mutant in the MAE52 strain background .
Consequently , we conclude that besides upregulation of RpoS , other Hfq-dependent factor are required to restore csgD morphotype expression in the hfq mutant of UMR1 .
This finding also suggests that bistable expression of csgD is regulated via RpoS and/or upregulation of promoter activity .
Adding to complexity , the alternative sigma factor RpoS not only activates and is activated by small RNAs , but also activates the csgD transcriptional regulator MlrA , while RpoS degradation is indirectly stimulated by RtsA .
Adding to complexity , the alternative sigma factor RpoS not only activates and is activated by small RNAs , but also activates the csgD transcriptional regulator MlrA , while RpoS degradation is indirectly stimulated by another csgD transcriptional regulator .
Adding to complexity , the alternative sigma factor RpoS not only activates and is activated by small RNAs , but also activates the csgD transcriptional regulator MlrA , while RpoS degradation is indirectly stimulated by another csgD transcriptional regulator .
Adding to complexity , the alternative sigma factor RpoS not only activates and is activated by small RNAs , but also activates the csgD transcriptional regulator MlrA , while RpoS degradation is indirectly stimulated by another csgD transcriptional regulator .