Fig. 5. Loss of DI1 interneurons in Bmpr double knockout animals. (A) At 10.5 dpc, Lhx2 is expressed by the dorsalmost, DI1A, population of sensory interneurons, arising adjacent to the roof plate in normal animals. (B) This population is absent in Bmpr double mutant animals, as shown by loss of Lhx2 expression. (C) Lhx9 marks the DI1B population of sensory interneurons in the dorsalmost neural tube at 10.5 dpc. (D) This population is completely absent in the Bmpr double knockouts, as shown by loss of Lhx9 expression. (E,F) TUNEL staining (red) at 10.5 dpc, shows no difference in TUNEL-positive cells in the dorsal neural tube of normal (E) and Bmpr double knockout (F) animals.