Figure 1.

APOL1-mediated cytotoxicity is both variant- and dose-dependent. (A) Schematic representation of plasmid DNA map of tetracycline-inducible APOL1 (monoallelic, G0 or G1 or G2) expression vector stably transfected into T-REx-293 cell line. (B–D) Western blot analysis of APOL1 protein levels in monoallelic T-REx-293 clones after 8 hours of tet induction using low (6.25 ng/ml), intermediate (12.5 or 25 ng/ml), or high (50 ng/ml) tet. (E–G) Clonogenic survival assay. After 9–14 days of tet induction, cell colonies were fixed with 100% ice-cold methanol and stained with 0.5% crystal violet. Colony counting was done using Image J software. (H–J) Survival fractions were calculated (refer to Methods) and dot plots were prepared using GraphPad Prism8. Statistical significances were calculated by comparing G0 with RRVs (G1 or G2). Error bar represents SD (*P<0.01; ***P<0.001).