Fig. 3. Interkinetic nuclear migration and mitosis of cortical apical progenitors are impaired in HD mouse embryos.

(A) Schematic of the experiment for analysis of interkinetic nuclear migration. E13.5 Hdh^Q7/Q7 and Hdh^Q111/Q111 embryos were electroporated with Cdt1-mKO2 and geminin-GFP constructs. After 48 hours, the movement of the GFP- and mKO2-labeled nuclei was followed by spinning disc microscopy, taking one image every 10 or 15 min for 10 hours. (B to D) Representative images showing the movement of nuclei in G₁, G₂, and G₁/S transition phases as indicated. (D) Stars indicate the beginning and ending of the G₁/S transition. Scale bars, 5 μm. (E) Quantitative differences in the velocity of G₁-phase nuclei [for each condition, n = 9 cells from three embryos from different mothers; ***P = 0.0008 (unpaired t test)], velocity of G₂-phase nuclei [for each condition, n = at least 202 cells from four embryos from different mothers; ***P < 0.0001 (Mann-Whitney U test)], and length of G₁/S transition [for each condition, n = at least 8 cells from three embryos from different mothers; *P = 0.0356 (unpaired t test)]. (F) Bar graphs show the percentage of phospho-histone 3 (PH3) cells (mitotic index) of dividing progenitors [E13.5: for each condition, n = at least 2151 cells from four embryos from different mothers, ***P < 0.0001 (unpaired t test); E15.5: for each condition, n = at least 1801 cells from three embryos from different mothers, ***P = 0.0005 (unpaired t test)]. Results are means ± SEM.