According to the idea that NO represses PhoPQ signaling , transcription of the PhoP-repressed genes ( prg ) fliA ( fig. 5B ) , fliC and hilA was upregulated in response to spermine NONOate treatment ( table S2 ) .
Induction of several PhoP-repressed genes including the SPI-1 transcriptional activator hilA , and fliA and fliC components of the flagellar type III secretion systems [ 47,53,54 ] further support a model in which RNS target PhoPQ signaling .