Fig. 4. Antp is necessary and sufficient for survival of the GW motoneuron. (A-B') NB7-3 neurons (dashed circles) in late stage 16 Drosophila Antp^W10 (A) and en-Gal4/UAS-Antp (B) embryos. Dashed lines mark the midline. (A',B') Magnified single scans of NB7-3 with GW outlined. (A'',B'') Only the activated Caspase 3 staining (act Casp3) is shown. Anterior is up in all images. (A) GWs undergo apoptosis in anterior thoracic segments of Antp loss-of-function mutants (arrowheads). Apoptosis in T3 and the abdomen is unchanged (arrows). (B) Ectopic Antp expression reduces apoptosis of GWs in T3 and abdomen (arrows). T2 is unaffected (arrowheads).