-RRB- b-galactosidase Activity b-galactosidase Activit SirA induction of invF requires HilD Previous evidence suggested that SirA required the HilC/HilD/RtsA binding sites in the hilA promoter to induce thus the entire SPI1 TTSS b-galactosidase Activity b-galactosidase Activit Fig. 5 .
-RRB- b-galactosidase Activity b-galactosidase Activit SirA induction of invF requires HilD Previous evidence suggested that SirA required the HilC/HilD/RtsA binding sites in the hilA promoter to induce expression of hilA .
In support of our model , we demonstrate that SirA induction of invF requires the presence of HilD .