The sitABCD operon is induced under iron-deficient conditions in the testinal tant is gesting is repressed by Fur .
The sitABCD operon is induced under iron-deficient conditions in-vitro is gesting is repressed by Fur .
The sit locus was constitutively expressed in the fur background , indicating that Fur acts as a repressor of sitABCD .
Fur is reported to repress the host-inducible , virulence-associated sitABCD iron acquisition genes .
For example , Fur has previously been shown to repress sitABCD , in Salmonella .
that Fur represses the sitABCD operon in the lumen