Fig. 1. Programmed cell death around the antennal nerve after adult eclosion. All images show frontal views of the fly brain [wild-type Canton-S (CS) after 6 hours of eclosion] with dorsal up. (A) Cells labelled with anti-cleaved caspase 3 antibodies are observed in various brain regions, including the area around the antennal nerve (an, arrowheads). Projection of confocal optical sections of the frontal half of the brain. Dashed lines outline the brain. The rectangle indicates the area shown in B,D-G. (B,D-G) A merged image (left) and single-channel images (insets) around the area of the labelled cells (arrowheads). A caspase-positive cell (B, arrowhead) was also TUNEL-positive and had a condensed nucleus. A TUNEL-positive cell (D, arrowhead) expressed the neural marker ELAV, but not the glial marker REPO. A caspase-positive ELAV-positive neuron (E, white arrowhead) sends its neurite towards the antennal nerve (yellow arrowhead). Projection of ten confocal sections. The cells that strongly expressed EcRA were also TUNEL-positive (F, arrowheads). A grim-expressing cell (G, whole-mount in situ hybridisation of grim mRNA) expressed the neural marker ELAV, but not the glial marker REPO (arrowhead). (C,H) Time course of the percentage of the antennal nerves with TUNEL-positive (C) and strongly EcRA-positive (H) cells. Colour coding of each bar indicates the percentage of antennal nerves with the indicated numbers of positive cells. The sample number (n) is indicated above each bar. an, cross-section of the root of the antennal nerve; al, antennal lobe; SOG, suboesophageal ganglion; vlpr, ventrolateral protocerebrum. Scale bars: 50 µm in A; 10 µm in B,D-G.