Figure 6. The DNA damage response is negative regulator of infection.

(A) WT MEFs or Mre11^ATLD MEFs, or (B) WT human fibroblasts (IMR90) and fibroblasts bearing a mutation in ATM (ATAG04405) were infected with L. monocytogenes expressing GFP for the indicated times. FACS analysis was performed on infected cells and the geometric mean of 10,000 cells was measured using the FlowJo software. Results are normalized to uninfected cells and averaged over at least 3 independent experiments. (C) HeLa cells were infected with L. monocytogenes expressing GFP for the indicated times. The ATM inhibitor was added (+ inhibitor) 1 h after the start of infection. FACS analysis was performed on infected cells and the geometric mean of 10,000 cells was measured using the FlowJo software. Results are normalized to uninfected cells and averaged over at least 3 independent experiments. (D) HeLa cells were transfected with the indicated siRNA and infected with L. monocytogenes. Cells were collected after 24 h of infection and immunobloted for the Listerial protein InlC (top). Quantifications (bottom) are normalized to actin and to the scramble sample over at least 3 independent experiments. All quantifications in graphs show the mean +/− SEM (* indicates that p<0.05, ** p<0.01).