dock and Pak are required in the antenna to regulate the precise projection of ON axons. (A,B) Confocal images of 30 hAPF antennae double-stained with anti-Dock (green) and 22C10 mAb (Futsch, red) antibodies. (A, left) In the wild-type antenna, Dock is clearly localized to the cytoplasm, apical dendrites and axon fascicles of bipolar neurons. (A, right) Merged image showing that Dock is co-expressed with Futsch in the neurons. (B, left) Dock protein is totally absent from the dock^P1/dock^P1 antenna. (B, right) Merged image reveals that ONs are present and apparently normal. (C,D) Confocal micrographs of tissues from ey-FLP/ Act5C>Raf>lacZ^nuclear animals, stained with an anti-b-galactosidase antibody. (C) The lacZ^nuclear gene is expressed in all cells of the eye-antennal disc. (D) With the exception of a few sporadic cells, lacZ^nuclear is not expressed in the AL region of the adult brain. (E) Eye-antennal disc of FRT82 Pak¹⁶ UNG/FRT82 M(3) arm-lacZ heterozygote in the absence of ey-FLP stained with anti-b-glactosidase antibody. All cells remain heterozygous. (F) Eye-antennal disc of FRT82 Pak¹⁶ UNG/FRT82 M(3) arm-lacZ heterozygote in the presence of ey-FLP. The disc becomes largely homozygous for Pak as evidenced by the loss of anti-b-glactosidasestaining. Scale bar: in C, 40 mm for C-F.

ON axon pathfinding and glomerular development in the dock-Pak compound heterozygote are normal. ALs of animals expressing UAS-mCD8::GFP under the control of SG18.1-Gal4 were stained with anti-GFP (green) and nc82 mAb (red) and examined by confocal microscopy. In the wild type (A), and in the dock/+ (B) and Pak/+ (C) heterozygotes, SG18.1-Gal4 expressing axons project in characteristic tracks on the AL surface and terminate in anatomically distinct glomeruli. (D) In the dock/dock homozygote, SG18.1-Gal4 axons form a homogenous mat and terminate in an amorphous neuropil. (E,F) In the dock/+; Pak/+ compound heterozygote, SG18.1-Gal4 axons project through axon tracks and terminate in distinct glomeruli that resemble those of wild type. Scale bar: 25 mm.

Olfactory neurons differentiate normally in dock and Pak mutants. (A-C) Confocal micrographs of eye-antennal discs stained with an anti-lozenge antibody. (A) In the wild-type antennal disc, lozenge is expressed in three semi-elliptical domains. In the dock^P1/dock ^P1 (B) and Pak⁶/Pak¹¹ (C) discs, the lozenge expression pattern is unchanged. (D-I) X-Gal stained antennae of animals expressing UAS-lacZ^nuclear under the control of Or22a-Gal4 (D-F) and Or47b-Gal4 (G-I). (D,G) In the wild type, Or22a ONs and Or47b ONs are expressed by characteristic numbers of neurons that are restricted to stereotyped domains in the antenna. The exact spatial arrangements of the neuronal cell bodies however, differ from one wild-type antenna to another. The distribution of Or22a ONs and Or47b ONs in (E,H) dock and (F,I) Pak mutants are similar to those of wild type. Scale bar: in D, 30 mm (D-I).

Olfactory sensilla develop normally in dock and Pak mutants. Adult antennae are cleared in Faure's mountant and photographed. (A) Wild-type antenna. (B) dock^P1/dock^P1 antenna. (C) Pak⁶/Pak¹¹ antenna. The sensilla on the mutant antennae have morphologies that clearly identify them as basiconic, trichoid or coeloconic. These different sensilla types are also found in numbers and topographically circumscribed domains similar to those of wild type. For example, the large basiconic sensilla are found exclusively in the proximomedial part of the antenna, while the coeloconic sensilla are irregularly distributed over the entire antennal surface. Representative examples of each sensilla type are indicated by colored dots at their bases. Blue, basiconic sensillum; red, coeloconic sensillum; green, trichoid sensillum.

Projection neurons and AL glia develop normally in dock and Pak mutants. (A-C) Confocal micrographs of adult ALs from animals expressing UAS-mCD8::GFP under the control of GH146-Gal4 driver, double stained with anti-GFP (green) and nc82 mAb (red). The dendritic arborization of the PNs in the dock (B) and Pak (C) mutants are more diffused compared with those in the wild type (A). The numbers of neurons in the three PN clusters are summarized in Table S1. (D-F) Confocal micrographs of adult ALs from animals expressing UAS-tubulin::GFP under the control of 1.3D2-Gal4 driver stained with anti-GFP. The distribution of glia around the AL and the extension of their glial processes in dock (E), Pak (F) mutants are similar to those of wild-type (D) animals. However, the number of glial processes may be somewhat reduced. adPN, anterior-dorsal PN cluster; lPN, lateral PN cluster. Scale bar: 25 mm.