Fig. 2. Numb is required for development of EW2 and EW3. All images are ventral cord abdominal segments from stage 17 embryos. The yellow numbers 1, 2 and 3 label the EW1, EW2 and EW3 neurons, respectively. M indicates the midline. (A,B) Immunostaining with Ddc (red), Zfh-2 (green) and Hb (blue) shows a preferential loss of EW2 cells in embryos homozygous for numb¹. The remaining Ddc-positive cells in numb¹ are Hb positive, indicating they are EW1 cells. (A'-B') Same images as (A,B), but showing only Ddc immunoreactivity. (C,D) Immunostaining with Ddc (red), Eg-lacZ (green) and corazonin (blue), showing a reduction of Eg-lacZ in numb¹ relative to wild type. Corazonin expression is completely absent in numb¹. Midline dopaminergic cells (M) are visible in wild type but are undetectable in numb¹. Scale bar in D: 5 µm for A-D.