Fig. 4. Dichaete regulates cell fate in the intermediate column. High-magnification ventral views of stage 9 wild-type (A-C), Dichaete (D-F) and Dichaete ind/ Dichaete + (G,H) mutant embryos labeled for ac (A,D,G) or ac (red) and ind (green; B,C,E,F,H). (A) In wild-type embryos ac is expressed in proneural cell clusters in the medial and lateral but not intermediate (arrows) columns of rows 3 and 7. (B,C) Normally, the expression of ind and ac is mutually exclusive in the neuroectoderm (arrows, B) and NBs (arrows, C). (D-F) In Dichaete embryos, ac expression is partially derepressed in the intermediate column (arrows, D) and intermediate column neuroectodermal cells (arrows, E) and NBs (arrows, F) inappropriately co-express ac and ind. (G,H) In Dichaete embryos heterozygous for ind, ac expression is strongly derepressed in the intermediate column (arrows, G) and ac and ind expression again colocalize in intermediate column neuroectodermal cells (arrows, H). Anterior is towards the left and the line indicates the ventral midline.
