Fig. 6. Persistent projection neuron pruning requires ultraspiracle and baboon. Anti-EcR-B1 staining (magenta) in single-cell MARCM clones (green) that are (A1) wild-type or homozygous for (A2) babo^Fd4 or (A3) usp³. At the onset of puparium formation, (A2) babo^Fd4 PPNs fail to express EcRB1, as indicated by the lack of nuclear magenta in the MARCM single-cell clone. At third instar larva, single-cell MARCM clones of PPNs homozygous for (B2) babo^Fd4 or (B3) usp³ exhibit apparent normal dendritic projections in larval AL compared with (B1) wild-type control. At third instar larva, single-cell MARCM clones of PPNs homozygous for (C2) babo^Fd4 or (C3) usp³ exhibit apparent normal axonal projections in larval MB and LH compared with (C1) wild-type control. At 8 hours APF, (D1) the majority of wild type PPNs have completely pruned their dendrites in the larval AL. However, many (D2) babo^Fd4 and (D3) usp³ PPNs still exhibit larval-like dense dendrites in the larval AL. At 8 hours APF, the majority of wild-type PPNs have largely eliminated their boutons in the MB calyx and pruned their axons back to the edge of the calyx (E1). By contrast, most (E2) babo^Fd4 and (E3) usp³ PPN axons still retain larval-like morphology, with large boutons in the MB calyx and terminal branches in the LH. (F) Cumulative pruning scores in larval AL, MB calyx and LH at 8 hours APF. L3 brains were stained with anti-mCD8 and nc82. At 8 hours APF, brains were stained with anti-mCD8 and anti-synaptotagmin. Slender arrows indicate dendrites in larval AL. Arrowheads indicate synaptic boutons in MB calyx glomeruli. Blunt arrows indicate axon termini in LH. L3, third instar larva; LAL, larval antennal lobe; WT, wild type.