Fig. 1

APOL1-induced nephrocyte phenotype is dose dependent. A Key APOL1 protein domains. Reference (G0) and risk allele (G1 and G2) amino acid variants in the SRA-binding domain have been indicated. BH3, Bcl-2 Homology 3; SRA, serum resistance-associated protein. B Western blot analysis of APOL1 protein using anti-FLAG antibody. Total protein was extracted from third instar larvae carrying Tub-Gal4 to drive APOL1-G0 and APOL1-G1 expression; wildtype (WT) larvae carried Tub-Gal4 only. Tubulin was used as an internal reference. C Quantification of relative APOL1 protein level based on the western blot analysis in B. N = 10 larvae per sample; four independent blots. Data represented as mean ± SD. D Representative images of 10 kD fluorescent dextran particle uptake (red) by nephrocytes from 20-day-old adult flies using nephrocyte specific driver Dot-Gal4 to express APOL1-G0 and APOL1-G1 constructs, and wildtype (WT) larvae with Dot-Gal4 only, at 22 °C. Hand-GFP transgene expression was visualized as green fluorescence located in nephrocyte nuclei. Dotted lines outline the individual nephrocytes. E Representative images of LysoTracker (red) in nephrocytes from 20-day-old adult flies using nephrocyte specific driver Dot-Gal4 to express APOL1-G0 and APOL1-G1 constructs, and wildtype (WT) larvae with Dot-Gal4 only, at 22 °C. Hand-GFP transgene expression was visualized as green fluorescence located in nephrocyte nuclei. Dotted lines outline the individual nephrocytes. F Quantification of 10 kD dextran uptake in D, relative to wildtype (WT) value. N = 30 nephrocytes total obtained from 6 flies. G Quantification of adult nephrocyte size, relative to wildtype (WT) nephrocytes. N = 30 nephrocytes total obtained from 6 flies. H Quantification of LysoTracker signal in E, relative to wildtype (WT) value. N = 30 nephrocytes total obtained from 6 flies. Results represented as mean ± SD, statistical significance (*) P < 0.05