Bap55 regulates projection neuron dendrite targeting. (A) Wild-type (WT) DL1 PN dendrites target specifically to the posterior glomerulus DL1 (yellow dashed circle in A2) and never target to the anterior glomerulus DA4l (yellow dashed circle in A1). White arrowhead denotes cell body in all images. (B) WT DL1 axons show an L-shaped pattern in the lateral horn (LH), with branches in the mushroom body calyx (MBC; both outlined with white dashed circles). (C) Bap55-/-PN dendrites fully mistarget to the anterior glomerulus DA4l (C1), abandoning the posterior glomerulus DL1 (C2). (D) Bap55-/-PN axons show the stereotypical L-shaped pattern in the LH with branches in the MBC. (E) WT GH146 anterodorsal neuroblast clones are characterized by their cell body location dorsal to the antennal lobe (white arrowhead in all images). The dendrites target to stereotyped glomeruli in the antennal lobe. (F) WT GH146 lateral neuroblast clones are characterized by their cell body location lateral to the antennal lobe with dendrites targeting to stereotyped glomeruli. (G) WT GH146 ventral neuroblast clones are characterized by their cell body location ventral to the antennal lobe with dendrites targeting across the antennal lobe. (H, I) Bap55-/-GH146-labeled anterodorsal (H) and lateral (I) neuroblast clones maintain their cell body location dorsal and lateral to the antennal lobe, respectively. Yet their dendrites do not target proper glomeruli. (J) Bap55-/-GH146-labeled ventral neuroblast clones maintain their cell body location ventral to the antennal lobe, yet their dendrites target a small area of the antennal lobe. Green marks mCD8-GFP-labeled PNs generated by MARCM and labeled using GH146-GAL4. (A, C) show partial confocal stacks; (B, D, E-J) show full confocal stacks; magenta is the presynaptic marker nc82; extraneous magenta punctate staining outside of the antennal lobe in some panels is dsRed background from the piggyBac and/or GH146-GAL4 insertions. Scale bars: 20 μm in (A) (for A, C, E-J) and (B) (for B, D).