FIGURE 5.

Effect of a α to γ iteron swap on propagation of a α-γ plasmid in an ihfΔ host. A, sequences of α and γ iterons. The sequence differences between the two are shown as underlying dots. B, schematic representations of the wt α-γ replicon and one with the α iteron replaced with a γ iteron. C, propagation of a normal and the iteron-exchanged α-γ replicon in IHF⁺ and ihfΔ hosts. D, ChiP data showing that in exponentially growing cells π protein remains bound to the iterons of γ but not to the α iteron; the lanes labeled marker, input, no Ab, and π Ab imm. ppt show a DNA ladder of different base pairs, PCR products of the α- and γ-specific primer pairs using a part of the input DNA as the template. no Ab., PCR products from mock-precipitated DNA; π Ab. imm. ppt, PCR products from cross-linked DNA immunoprecipitated with anti π Ab, respectively. The subcolumns corresponding to the input, mock immunoprecipitation, and π Ab immunoprecipitation, labeled as α, γ, and αγ, refer to primer pairs used to amplify either each iteron region separately or together.