Refining NB drivers by intersection. (A-C) Via activation of dpnEE>KDRTs-stop-KDRTs>LexA::P65, the drivers R14D11-GAL4 (A) and R41A10-GAL4 (B) show activities (green) in MB NBs (yellow arrowheads) plus various non-overlapping NBs (white arrowheads). Intersection with the split GAL4 components, driven respectively by R14D11 and R41A10, achieves exclusive targeting of MB NBs (C). The CNS of 50 h ALH larvae was counterstained for Bruchpilot with nc82 mAb (blue). (D-F) Analogously, combining R44F03 with ems allows specific targeting of AL NBs. (G-I) stg-KD selectively activates dpn>KDRTs-stop-KDRTs>GAL4 in type II NBs plus various type I NBs (G). asense-GAL80 can repress GAL4 activity in type I NBs (H). Combining stg-KD with asense-GAL80 achieves exclusive targeting of type II NBs, which lie next to their derived INPs marked with R9D11-LexA::P65 (magenta) (I). Insets show that NBs (arrows) are much larger than their offspring. Scale bars: 20 µm.