Fig. 7

(A) Confocal images of whole-mount immunofluorescence performed on 72-hpf embryos lens by using MKLP1 (red) and Aur-B (green) antibodies to stain midbody and TO-PRO-3 (gray) to stain nuclei. (B) Quantification of number of MKLP1 and Aur-B–positive midbody in 72-hpf embryos lens. (C) Measure of lens area in control and vps36 morphants. (D) Immunoblot analysis and quantification of p16INK4A in control and vps36 morphant 72-hpf embryos. n = 4 pools of 15 embryos each. (E) Quantification and representative images of SA-b-gal intensity on the lens of control and morphant (vps36) 72-hpf embryos. (F) During cytokinesis, PI3K-C2α produced PI(3,4)P2 (red) at the midbody by converting PI(4)P (light blue) synthetized by PI4KA. PI(3,4)P2 triggers the recruitment and the stabilization of the ESCRT-II subunits VPS36 (green), which in turn contributed to the accumulation of ESCRT-III CHMP4B at the midbody. When PI3K-C2α is lost, the secondary ingression where abscission occurs does not form properly, resulting in impaired abscission. This leads to defective cytokinesis and early onset of senescence, which is particularly evident in the lens epithelium. If not previously specified, all results are shown as mean or representative picture of at least three independent experiments ± SEM. ***P < 0.001.