Figure 3

Opposing function of Shh and Pax6 in regulating formation of the habenula. (A-P) ISH for Irx1, Pou4f1, Nrp2 and Etv1 on sagittal (A-L) and coronal (M-P) sections of E14.5 embryos of indicated genotypes. Insets show coronal sections of E14.5 embryos. Red dashed lines indicate the posterior border of the thalamus demarcated by the FR tract (arrow); green dashed lines demarcate the posterior limit of the habenula; red brackets show the habenular nuclei; red and green asterisks indicate the loss and ectopic expression of habenular markers, respectively; empty arrowheads show abnormal defasciculating axonal fibers replacing the FR tract. Scale bar in (A): 200 μm (A-L); 170 μm (M-P); 711 μm (insets). E, embryonic day; FR, fasciculus retroflexus; ISH, in situ hybridization.