Fig. 9. (A-F) Expression pattern of GmDelta. Flat preparations of whole embryos (A,B) and leg segments (C-F) stained for a DIG-labelled GmDelta probe. (A,B) GmDelta transcripts can be detected at low levels in all ventral neuroectodermal cells, but they accumulate at higher levels in the invaginating cell groups. In addition, the gene is expressed in groups of cells in the limb buds and dorsal to the limb buds (arrowheads). These regions coincide with the generation sites of the peripheral nervous system. (C) Accumulation of higher levels of GmDelta transcripts is first visible during formation of the first invagination sites at stage 2 (arrow). (D-F) High levels of GmDelta expression correlate with the formation of invagination sites throughout neurogenesis (arrows). The expression is rapidly downregulated during the process of invagination, although the low uniform expression in all neuroectodermal cells is maintained. l1 to l6, leg segments 1 to 6. Scale bars: 120 µm in A,B; 50 µm in C-F.