Fig. 7

Loss of Pax6 expression at E12.5 in CAGG ^Cre; Pax6 ^loxP/loxP embryos delays thalamic axonal growth. a, b Pax6 immunohistochemistry shows a loss of Pax6 expression at E12.5 throughout the brain in CAGG ^Cre; Pax6 ^loxP/loxP embryos compared to controls. c–j DiI placement in the thalamus (Th) labels TCAs extending through the prethalamus (PTh), avoiding the hypothalamus (Hy) and crossing the ventral telencephalon (vTel) to the cortex (Cx) in both control and CAGG ^Cre; Pax6 ^loxP/loxP embryos between E13.5 and E16.5. c, d At E13.5, most axons in the control cross the diencephalic-telencephalic boundary (DTB) and are half way through the ventral telencephalon, whereas in CAGG ^Cre; Pax6 ^loxP/loxP embryos, the advancement of axons is delayed (white bar shows the distance between the tips of the TCAs and the pallial-subpallial boundary [PSPB]). GE = ganglionic eminence. e, f A large number of axons in the control have crossed the PSPB at E14.5 but the axons in CAGG ^Cre; Pax6 ^loxP/loxP embryos remain in the ventral telencephalon. g, h In control embryos at E15.5 TCAs navigate further into the cortex whereas in CAGG ^Cre; Pax6 ^loxP/loxP embryos some axons just cross the PSPB. i, j By E16.5 TCAs have reached the cortex in both CAGG ^Cre; Pax6 ^loxP/loxP and control embryos. Hip = hippocampus. Scale bars, 500 μm