Induction of apoptosis-related gene mRNAs in HGF cells infected with wild type P. gingivalis (Triangles) or its triple gingipain mutant (Circles). Total mRNA from infected cells at different times p.i. were subjected to quantitative Real Time RT-PCR as described under Materials and Methods, using primers described in Table 1. The relative amounts of RNA were expressed as the ratio of uninfected control value (fold induction). Each box represents a specific gene as named and its generally accepted nature as anti-apoptotic ('anti') or pro-apoptotic ('pro'). Each data point is derived from three independent infection experiments with the error bar as shown. Note the general trend of early activation of anti-apoptotic genes (upper rows) and late activation of the pro-apoptotic ones (lower rows). Treatment with LY294002 (Closed circles) and SN50 (Closed triangles) inhibited activation of anti-apoptotic genes, as exemplified by Bfl-1.