Figure 5. Expression of NleH-GFP upon E. coli O157:H7 ZAP193 contact with EBL cells.

ZAP193 transformed with plasmids expressing GFP constitutively (pAJR145; rpsm::gfp) or translational fusions of nleH or tir to gfp under the control of their native promoter (pAHE8; NleH1-GFP, pAHE22; NleH2-GFP, pAJR75; Tir-GFP) were added to EBL cells and incubated for 0, 5, 30, 60 or 180 minutes at 37°C, 5% CO₂ before the removal of supernatant and fixation of cells with 4% paraformaldehyde. The panel of images is representative of all time points tested, apart from Tir-GFP, that showed strong early expression during cell contact but was markedly reduced at 180 minutes.