Expression of Pdu-sna2 in neural precursors and foregut cells. (A) is a confocal picture of a WMISH showing expression of Pdu-sna2 in the developing VNC and the foregut. The asterisk indicates the position of the foregut. (B) and (C) are virtual cross-sections which have been made at the levels indicated by the dashed lines in (A). Apical is up, basal is down. (B) Pdu-sna2 is expressed in cells belonging to the developing foregut (arrows). (C) Layers of the VNC region have been previously defined . Pdu-sna2 is mainly expressed in the intermediate layer (post-mitotic undifferentiated neural precursors; a few of them are indicated by arrows).