To test the hypothesis that FliZ may operate through FliT , we compared tetRA background to control for flhDC autoregulation -LRB- Fig. 4B -RRB- .
One possibility is that FliZ regulates flhDC transcription .
In the related insect pathogen Xenorhabdus nematophila , FliZ was recently shown to bind to the flhDC promoter .
Likewise , our data show that FliZ is not a transcriptional regulator of the flhDC operon in S. enterica serovar Typhimurium , whereas it is in X. nematophila .