Fig 4.

OhrR binds to an OhrR box in the ohr-ohrR intergenic region of B. abortus 2308. DNase I footprint analysis was employed to determine the exact nucleotides bound by OhrR in the ohr-ohrR intergenic region. The forward or reverse strands of ohr-ohrR intergenic region DNA were individually radiolabeled, and the labeled DNA fragments were incubated with increasing concentration of rOhrR protein. Following treatment with DNase I, the digested DNA fragments, along with the corresponding DNA sequencing reaction products (shown as G, A, T, or C along the top of the gel), were separated on 8% denaturing polyacrylamide gels and visualized by autoradiography. The region of the DNA fragment protected by rOhrR is listed vertically on the right side of each gel.