HEK293 cells were stably transfected with empty vector (EV) or APOL1 reference G0, or G1, or G1 kidney-risk variants in a “Tet-On” system, so that Dox treatment (“Tetracycline-On”) could induce expression of the APOL1 reference or variant gene product. EV G0, G1 and G2 refer to HEK293 Tet-on cells of different APOL1 genotypes.
First, mitochondrial length was evaluated in HEK293 Tet-on cells conditionally expressing EV, APOL1 reference allele G0, and kidney risk variants G1 and G2 in cells cultured in cell growth media pH 6.8 or 7.4 after 24 hours without Dox-induction (without APOL1 expression; upper panel).
Second, mitochondrial length was evaluated in cells incubated in Dox-free cell growth media pH 6.8 or 7.4 for 16 hours and then switched to Dox-induction for 4, 6 and 8 hours in cell growth media pH 6.8 or 7.4 (lower panel).