Figure 2.

Development of the hindbrain roof plate is dependent on overlapping functions of Lmx1a and Lmx1b. A–H, Dorsal view of whole-mount in situ hybridization of E10.5 embryos using probes for Gdf7 and Wnt1. The brackets in A and B indicate the position of rh1 and the future cerebellum. The line in B specifies the level of the transverse section in I. C, D, In Lmx1b^−/− embryos, the fourth ventricle roof plate was nearly normal despite the loss of the IsO. E, F, The fourth ventricle roof plate was reduced in Lmx1a^−/− embryos. G, H, Lmx1a^−/−; Lmx1b^−/− embryos had little or no residual fourth ventricle roof plate (red arrow). The line in H indicates the transverse section in K. I, Schematic of a transverse section of the fourth ventricle. The boxed region indicates equivalent region in J and K. J, In wild-type embryos, the roof plate covered the fourth ventricle. K, This region was lost in Lmx1a^−/−; Lmx1b^−/− embryos, although residual, lateral non-roof plate Wnt1 expression remained. IV, Fourth ventricle.