Figure 10
Sp8 changes region-specific gene expression in the cortex. (a, d, g, j) Dorsal views of P1 brains processed for whole mount in situ analysis with digoxigenin labeled-cad8 riboprobes following electroporation at an anterior (a, d), or posterior (g, j) location of empty control (a, g) or Sp8 (d, j) vectors at E11.5. Arrowheads indicate the posterior border of the cad8 expression domain in anterior cortex. Anterior electroporation of Sp8 results in an anterior contraction of the cad8 domain (d), whereas posterior electroporation of Sp8 results in a posterior expansion of the cad8 domain (j). Electroporation of an empty vector has no effect on the cad8 domain (e, m). (b-f, h-l) Sagittal sections of P1 brains stained with an anterior marker gene, RORb probes (b, e, h, k), or a S1 marker gene, ephrin-A5 probes (c, f, I, l), following electroporation at an anterior (b, c, e, f) or posterior (h, I, k, l) domain of empty vector (b, c, h, i) or Sp8 (e, f, k, l). Arrowheads indicate the posterior border of the RORb expression domain or the putative M1/S1 and S1/V1 borders of ephrin-A5 expression. Coincident to the area shifts detected by cad8 expression, RORb and ephrin-A5 expressions are shifted anteriorly in anterior Sp8-overexpressed brains, and shifted posteriorly in posterior Sp8-electoporated brains. Scale bars: 0.5 mm (e, f, m, l); 0.5 mm (b, c, e, f, h, I, k, l). (m) Quantification of cad8 expression domains in Sp8- or control transfected brains. Anterior electroporation of Sp8 reduces motor area (MA) size detected as cad8 domain (8.2 ± 1.12%, SEM, n = 13) compared to the control cases (15.2 ± 0.297%, SEM, n = 9). In contrast, posterior electroporation of Sp8 enlarges motor areas (19.97 ± 0.771%, SEM, n = 6) compared to the control cases (14.37 ± 0.241). The bottom panel shows a scatter plot of individual cases. EP, electroporation.