FIG 2.

ClbR is a regulator of colibactin expression. (A) HeLa cells were either infected with E. coli strain M1/5 rpsLK42R and derivatives (multiplicity of infection [MOI] of 100) or not infected. After 4 h of infection, HeLa cells were washed to remove bacteria and further cultivated. At 48 h postinfection, cells were washed and the cell morphology was analyzed by phase-contrast microscopy. Scale bars: 200 μm. (B) G₂ cell cycle arrest. An increased number of sub-G₁ cell populations (cell death) present after DNA damage were assayed by flow cytometry. (C) At 4 h postinfection, bacteria were removed and the cells were cultivated for another 4 h and subsequently washed with phosphate-buffered saline (PBS) and lysed. A total of 4 μg protein per lane of the indicated samples was analyzed by SDS-PAGE and afterwards transferred onto a polyvinylidene difluoride (PVDF) membrane. γ-H2AX was detected using anti-phospho-histone H2AX (Ser139) antibody (Millipore). β-Actin served as a loading control.