Fig. 1

Ki-67 degradation delays S phase progression. A Scheme of Ki-67 protein structure and domains (Ki-67 wt) and the endogenously tagged version (Ki-67-AID) generated in the HCT116 cell line. B Representative image of the HCT116:Ki-67-AID cell line without (top panels) and with (bottom panels) auxin. Ki-67 is in green and DNA in blue. Scale bar 10 μm. C Growth curves of the HCTT116 parental (Ki-67 wt) and degron tagged HCT116:Ki-67-AID (Ki-67-AID) cell lines without and with (+ auxin) doxycycline and auxin. The values represent the average of 4 independent experiments. The error bars represent the standard deviations. D Flowcytometry profiles of the HCT116:Ki-67-AID cell line grown with (auxin—right) and without (control—left) auxin. The numbers represent the percentage of cells in each stage: green G1; yellow S; cyan G2/M. E Scheme of the experiment for (F-H). EdU was added 30′ before each time point. Thy = thymidine. F The graph represents the percentage of cells EdU positive at the different time points. The values are the average of 5 biological replicas and the error bars represent the standard deviations. Sample sizes: control 3 h = 723, 4 h = 922, 6 h = 847; auxin: 3 h = 1207, 4 h = 1108, 6 h = 1037. The data were statistically analysed with a chi-squared test (control vs auxin). ***p < 0.001. G Representative images of EdU patterns for early (bottom panel), middle (middle panel) and late (top panel). H Distribution of the replicating cells according to the patterns shown in (G) from the experiment in (F–H). I Scheme of the experiment for (J–K). EdU was added 30′ before each time point. Thy = thymidine. J The graph represents the percentage of EdU positive cells at the different time points. The values are the average of 3 biological replicas and the error bars represent the standard deviations. Samples size: control: 6 h = 570, 8 h = 758; auxin: 6 h = 945, 8 h = 813. The data were statistically analysed with a chi-squared test (control vs auxin). ***p < 0.001. K Distribution of the replicating cells according to the patterns shown in (G) from the experiment in (J–K)