Fig. 1

Septin-depleted cells undergo significantly less apoptosis. (a) HeLa cells were transfected for 72 hr with control (CTRL) siRNA or a siRNA targeting SEPT7. Effect of siRNA on SEPT7 expression. A representative Western blot of HeLa cell lysates is shown. GAPDH was used as a loading control. (b) Impact of siRNA targeting SEPT7 on viability of HeLa cells in (i) untreated or (ii) STS-treated conditions. Cell viability is measured using MTT assays as described in Materials and Methods. Data are mean ± SEM from three independent experiments. **p = .0069 by two-tailed Student's t test. (c) HeLa cells were transfected for 72 hr with control (CTRL) siRNA or a siRNA targeting SEPT2. Effect of siRNA on SEPT2 expression. A representative Western blot of HeLa cell lysates is shown. (d) Impact of siRNA targeting SEPT2 on viability of HeLa cells in (i) untreated or (ii) STS-treated conditions. Cell viability is measured using MTT assays as described in Materials and Methods. Data are mean ± SEM from three independent experiments. ***p = .0004 by two-tailed Student's t test. (e) Control and SEPT7-depleted cells were treated with DMSO or 1 μM STS or 500 μM ETP for 10 hr and labeled with Alexa488-Annexin V (Annexin V) and Hoechst. Representative widefield microscopy images showing Annexin V in green and Hoechst in blue. Scale bar = 100 μm. (f) The % of Annexin V positive cells is calculated in Fiji by dividing the number of cells that displayed Annexin V labeling by the total number of cells identified by nuclear Hoechst labeling, then multiplying by 100. Each bar represents the mean % ± SEM from three independent experiments (a minimum of 1,000 cells were counted per condition separated in three independent experiments). ****p < .0001by two-way ANOVA.