Figure 1.

Mllt11 is expressed in the developing CP and Mllt11 loss affects the laminar distribution of cells. A, Coronal sections of the targeted Mllt11 locus (which inserted a lacZ cDNA) showing Mllt11 expression across four time points during cortical neurogenesis through β-Gal staining. At E14.5, β-Gal expression was most intense in the CP, corresponding to UL neurogenesis. By E16.5, β-Gal staining intensity shifted to the superficial cortex where UL CPNs were accumulating. B–D, Body weight (B), brain weight (C), and brain weight as a percentage of body weight (D) showed no difference between control (cntl) and cKOs at E18.5. E, cKO cortices were thinner than controls at E18.5. F–H, Thinning of the cKO cortex was progressive, with thicknesses being comparable to controls at E14.5 (F), but Mllt11 mutants exhibited reduced thickness and reduced distribution of cells in the superficial cortex at E16.5 (G), which increased in severity by E18.5 (H). Total cell counts and cortical thickness measurements (µm) are shown as bar graphs. Cell count line charts represent percentage of positive cells normalized to DAPI+ nuclei per 100 × 100 μm bin. Student's t test with Welch's correction, (B–D) N = 8, (F) N = 5, (G) N = 7 for total cells, N = 5 for cortical thickness, (H) N = 5 for total cells, N = 4 for cortical thickness. Data presented as mean ± SD n.s., not significant; *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001, ****p ≤ 0.0001. Scale bars: 100 μm (A), 100 μm (E), 50 μm (F–H). Ctx, cortex; CP, cortical plate; IZ, intermediate zone; LGE, lateral ganglionic eminence; MGE, medial ganglionic eminence; MZ, marginal zone; PP, preplate; SP, subplate; VZ, ventricular zone. See Extended Data Figures 1-1, 1-2, 1-3, 1-4, 1-5.