Figure 3

Expression patterns of Sp8 in embryonic mouse forebrain and relationships with expression domains of Fgf8 in the CoP. (a-i) Shown are in situ hybridizations of sections of mouse forebrain at E10.5 to E13.5 using DIG-labeled riboprobes for Sp8 on sagittal (a, d, g) or coronal (b, e, h) sections, and for Fgf8 (c, f, i). Sp8 is expressed in the dTel VZ, with highest levels in the medial and anterior parts. Sp8 is also expressed robustly in the LGE and at lower levels in the MGE. Sp8 expression overlaps the Fgf8 expression domain in the CoP at E10.5 (arrowhead in (b, c)), but gradually become excluded at E11.5 (arrowhead in (e, f)). (j, k) Whole mount in situ hybridizations done on E9.5 embryos with DIG-labeled riboprobes for Sp8 (j), and Fgf8 (k), respectively. The Sp8 A/P gradient is evident at this stage (j). Arrowheads indicate expression domains. Ctx, cortex; GE, ganglionic eminence; Hp, hippocampus. Scale bars: 0.5 mm (a-f); 0.5 mm (g-i); 0.5 mm (j, k).