Figure 5.

Br-Z3 expression in specialized brain regions. (A, B) Expression of Br-Z3 in neurons of the mushroom bodies. (A) A projected confocal z-stack showing an embryonically induced MARCM clone in the mushroom bodies of a mid third instar larva. Two individual sections from the red-framed area are on the right and show the expression of Br-Z3 (magenta) in the green fluorescent protein (GFP)+ (green) cells of the clone. Only the neuroblast (NB) and its most recently born progeny lack Br-Z3 expression. (B) A projected confocal Z-stack of a pharate adult brain (95 h APF) showing the four small clusters of Br-Z3 expressing neurons in the mushroom bodies (arrows). OL, optic lobe. (C, D) The changes of Br-Z3 expression in the optic lobe through early metamorphosis. (C) The progression of Br-Z3 in the neurons of the optic lobe. The confocal images at late wandering show a complete Z-projection (W(P)) and a confocal single slice (W). Br-Z3 expression is strong in the lamina (la) and medulla (m) but only the neurons in the most medial columns of medulla express Br-Z3. Subsequent sections show recruitment of more lateral medulla columns (arrows) in older prepupae (hours APF) with the inclusion of all of the medulla neurons by 14 h APF. 14(P): a full Z-projection of the 14 h preparation. In the sections, the arc indicates the extent of Br-Z3 expression in the medulla. (D) Br-Z3 expression in a confocal Z-projection at 27 h APF. Br-Z3 expression is still present in neurons of the medulla and lobula and lobula plate (lo/lp) even though it has disappeared from all other regions of the CNS except the mushroom bodies.