FIG. 6.

Autoradiogram of a nondenaturing 8% polyacrylamide gel with purified SarA protein and a 198-bp γ-³²P-radiolabeled DNA fragment containing the intergenic promoter region of the icaRA genes. A. Lanes 1 to 6, mobility of the 198-bp radiolabeled DNA fragment (≈3 ng) of the S. aureus icaRA promoters region in the presence of 0, 50, 100, 200, 300, and 500 ng of purified protein, respectively; lanes 7 and 8, mobility of the same fragment with 300 ng of SarA, but in the presence of a 100-fold excess (molar ratio) of the unlabeled 198-bp fragment as the specific competitor (lane 7) and a 100-fold excess of unlabeled 148-bp intergenic sarUT promoter fragment (36) as the nonspecific competitor (lane 8). Lanes 9 to 16 are similar to lanes 1 to 8 except that the 198-bp fragment was from the ica promoter region of S. epidermidis. B. The nucleotide sequence of the 198-bp fragment containing the ica intergenic region of S. aureus (AF086783) and S. epidermidis (U43366) is shown and marked with the putative binding regions for SarA protein as determined based on the SarA consensus binding site (6).