FIGURE 3.

Effect of iron and manganese on Irr occupancy of the mntH and irr promoters in vivo in cells of the wild type and fur mutant strain. A and B, cross-linking and immunoprecipitation of wild type (Wt) or fur mutant cells grown with the various iron and manganese conditions were carried out as described in Fig. 2, except that anti-Irr antibodies were used. The data are expressed as the SQ of immunoprecipitated DNA normalized to the mock pull down. C, Western blot analysis of Irr protein levels in cells of the wild type or fur mutant grown under the iron and manganese conditions described above. 50 μg of protein was loaded per lane.