Here , we show that the chiP gene , like the chbBCARFG operon , is also downregulated at the transcriptional level by the NagC repressor .
Inactivation of the NagC repressor causes chiP expression to increase no more than twofold to threefold in ΔchiX background .
The NagC repressor inhibits chiP transcription under uninduced conditions through binding to the chiP promoter .
The NagC repressor inhibits chiP transcription under uninduced conditions through binding to the chiP promoter .
However , in both organisms repression of chiP by NagC is inefficient resulting in a relatively high basal level of chiP transcription in the absence of chitobi-ose .
Second , as the flux of chitobiose through the ChbBCA ChbFG enzymes relieves repression by NagC of both chiP operons .
Second , as the flux of chitobiose through the ChbBCA transporter enzymes relieves repression by NagC of both chiP operons .
In uninduced the chb , chiP operons are repressed by NagC .
In the absence-of-chitosugars the chb , chiP operons are repressed by NagC .