Fig. 4. Abd-B, but not other Hox genes, can fully prevent apoptosis of anterior dMP2 neurons. Postmitotic ectopic expression of specific Hox genes using dMP2-GAL4. dMP2 neurons are visualized by simultaneous expression of UAS-nls-myc-EGFP. No anterior dMP2 neurons survive in late embryos (air-filled stage) expressing Antp (A) or Abd-A (C). Ubx expression results in occasional rescue (B, arrow), and only Abd-B expression can prevent anterior death robustly (D). White numbers in A-D indicate the percentage of anterior dMP2 neurons rescued using dMP2-GAL4 (n>8 VNCs for each genotype). Percentages in yellow were obtained using elav^GAL4 and staining dMP2 neurons with Odd (not shown; n>8 VNCs for each genotype). (I,J) Anterior dMP2 neurons rescued by ectopic Abd-B expression express Odd in late embryos (I, 100%, n>100 neurons) and, in larvae, Proctolin (J, 70%, n=38 neurons). (E-H) All four transgenes are robustly expressed at stage 16, just before anterior dMP2 neurons begin to die. For purposes of clarity, segments with no endogenous expression of the relevant Hox gene are displayed.