Extended Data Fig. 6: Increased mitotic cells in the SVZ of the Cep83 cKO cortex are predominantly IPs.

(a) Images of E15.5 WT and Cep83 cKO cortices stained for P-HH3 (red), a mitotic cell marker, and with DAPI (blue). Scale bar: 50 μm. (b, d) Images of E15.5 WT and Cep83 cKO cortices stained for P-HH3 (red) and TBR2 (green, d) or SOX2 (green, f), an RGP marker, and with DAPI (blue). High magnification images of individual P-HH3⁺ cells are shown at the bottom. Note that P-HH3⁺ cells in the SVZ of the Cep83 cKO cortex are predominantly TBR2⁺, but SOX2⁻. Scale bars: 25 μm and 10 μm. (c) Images of E15.5 WT and Cep83 cKO cortices stained for P-HH3 (red) and phospho-VIMENTIN (P-VIM, green), and with DAPI (blue). High magnification images of individual P-HH3⁺ cells are shown at the bottom. Scale bars: 50 μm and 10 μm. (e, f) Quantification of the number of apical (e) and basal (f) P-HH3⁺ cells per 250 μm column. WT, n = 16 brains; Cep83 cKO, n = 14 brains. (g, h) Quantification of the percentage of P-HH3⁺ cells in the SVZ that are TBR2⁺ (g; lateral: n = 4 brains for each genotype; medial: n = 3 brains for each genotype) or SOX2⁻ (h; n = 4 brains for each genotype). (i) Quantification of the percentage of P-HH3⁺ cells without a P-VIM labelled basal radial glial fibre (lateral: n = 4 brains for each genotype; medial: n = 3 brains for each genotype). (j-l) Representative images of E15.5 WT and Cep83 cKO cortices stained for PAX6 (green) and HOPX (red, j), PTPRZ1 (red, k), or TNC (red, l), three previously suggested oRG markers, and with DAPI (blue) (n = 4). Note no obvious increase in HOPX, PTPRZ1, or TNC expression in the Cep83 cKO cortex and low expression in both WT and Cep83 cKO cortices. Scale bars: 50 μm. For box-whisker plots: centre line, median; box, interquartile range; whiskers, minimum and maximum. Statistical analysis was performed using two-sided Mann-Whitney-Wilcoxon test.