Together with the finding that induction of the feoB gene was necessary for repression of the iron response by the RstA protein ( Fig. 3B ) , our results suggest that iron signaling via the RstA-induced FeoB promotes Fur activity beyond the levels which are simply accomplished by iron .
We propose that the RstA-induced feoB expression allows Salmonella cells to take up more Fe ( II ) , thereby promoting Fur activity [ as evidenced by Fur-Fe ( II ) levels ] based on the following .
Activation of feoB transcription by the RstA protein is necessary for repression of iron-responsive genes .
Together with the finding that induction of the feoB gene was necessary for repression of the iron response by the RstA protein ( Fig. 3B ) , our results suggest that iron signaling via the RstA-induced FeoB promotes Fur activity beyond the levels .
This emphasizes that , in the presence of iron , the feoB gene should be induced by the RstA protein to repress iron-responsive genes .