Regulation of cell viability by overexpression of WT1 (−KTS), but not WT1 (+KTS). (A) MTT assays of immature rat GCs transfected with one of the two WT1 isoforms. GCs transfected with WT1 or empty vector were incubated with or without serum for 24 h. Some cells were treated with FSH (50 ng/mL) as a positive control for survival factors. After the cells were incubated with tetrazolium salt solution for 2 h, the quantity of formazan product was determined from the absorbance at 570 nm. Each bar represents the fold change compared to control (CT). (B) analysis of caspase 3/7 activity. GCs transfected with WT1 or empty vector were incubated with or without serum. Some cells were treated with FSH (50 ng/mL) as a positive control for apoptosis suppressors. 24 h later, caspase 3/7 activity was measured with the bioluminescence assay. (C) Immunoblot analysis of WT1 protein in cultured GCs lysates to confirm WT1 overexpression. Bands corresponding to WT1 (52 kDa), and β-actin (42 kDa), respectively. CT, empty vector-transfected cells cultured without serum for 24 h. WT1 (−KTS) (100 ng/well); WT1 (+KTS) (100 ng/well); FBS, 10% fetal bovine serum. Data are expressed as the mean ± SD of three separate experiments. *p < 0.05 compared to control.