Fig. 2. Gdf7 activation in DM neuroepithelium at neural tube stages. X-gal stains of Gdf7Cre;R26R embryos (A-D) and coronal sections (E-G), and wild-type Gdf7 in situ hybridization (H); rostral is rightwards in A, towards the top in B-D. (A,B) E9.5 embryos. lacZ is weakly detected in the DM throughout the CNS, including the telencephalon (arrow in A) and hindbrain (arrowheads in B). (C,D) E10.5 embryos. lacZ is more readily detected in the DM of the telencephalon (arrow in C), diencephalon (C) and hindbrain (arrowheads in D). The telencephalic and diencephalic DM domains are separated by weaker staining at the di-telencephalic midline boundary (C). (E,G) E10.5 telencephalon. Labeling is detected in many, but not all, DM neuroepithelial cells in the roof plate (rp). Little to no labeling is seen laterally in the cortical primordia (cx) or radially in the overlying mesenchyme (m) and surface ectoderm (s). (F,H) E10.5 hindbrain. X-gal staining (F) and Gdf7 transcripts (H) are primarily localized to RP neuroepithelium and its junction with the cerebellar anlage (cbl), with little to no expression in surface ectoderm or overlying mesenchyme (s/m). Scale bars: 0.1 mm.