FIG 6.

Pol IV localization after double-strand break induction in exponentially growing cells. (A) Phase-contrast, fluorescence, and overlay images of LacI-ECFP and DinB-EYFP foci in cells carrying an I-SceI recognition site 161 kb from the lacO array. The cells were grown in LB broth at 37°C to early exponential phase (OD₆₀₀, ∼0.1), induced for LacI-ECFP and I-SceI endonuclease, incubated for an additional 1.5 h, and then visualized (see Materials and Methods). Scale bar = 5 μm. Arrows indicate representative colocalized foci. (B) Percentages of cells with LacI-ECFP and DinB-EYFP foci. Shown are means ± SEM. (C) Percentages of cells with DinB-EYFP foci colocalizing with LacI-ECFP. Shown are means ± SEM. WT, PFB1081 carrying plasmids pPFB1035 and pPFB913 (DinB-12L-EYFP); the data are from three independent experiments with 108, 160, and 101 cells observed. ΔdinB, PFB1103 carrying plasmids pPFB1035 and pPFB913 (DinB-12l-EYFP); the data are from three independent experiments with 101, 85, and 69 cells observed. ΔumuDC, PFB1195 carrying plasmids pPFB1035 and pPFB1188 (DinB-20L-EYFP); the data are from two independent experiments with 198 and 207 cells observed. ΔdinB ΔumuDC, PFB1201 carrying plasmids pPFB1035 and pPFB1188 (DinB-20L-EYFP); the data are from three independent experiments with 146, 230, and 189 cells observed.