Sensilla containing the normal pb1 configuration, consisting of a pb1A cell paired with a pb1B cell, are not found in acj6⁶ mutants. pb1A cells are not observed; rather, most sensilla contain two pb1B cells that are paired in the same sensillum (pb1B, pb1B), and a smaller fraction of sensilla contain a normal pb1B cell that is not paired with a responsive neuron.

No defects in pb1A olfactory receptor neuron response are seen in heterozygous acj6⁶ mutant flies.

In acj6⁶ homozygous somatic clones DL1 adPN have diffuse dendrites which innervate surrounding antennal glomeruli as well as DL1.

pb3A olfactory receptor neurons (ORNs) are never observed but pb3B ORNs are unaffected.

The boundaries of some olfactory receptor neuron glomeruli appear less discrete in acj6⁶ hemizygous males.

A specific subset of olfactory receptor neuron (ORN) axons show targeting defects in acj6⁶ hemizygous males. Or47b-, Or85e- and Or88a-positive ORN axons are targeted normally. In contrast, Or43a- (glomerulus DA4), Or47a- (glomerulus DM3), Or83c- (glomerulus VA6 and sometimes glomerulus DA3), Or59c- (glomerulus 1) , Or71a- (glomerulus VC2) and Gr21a- (glomerulus V) positive ORN axons do not target appropriately in acj6⁶ mutants. Although in each case ORN axons enter the antennal lobe, they spread over a larger region, sometimes including the appropriate area, and often form ectopic clusters. These ectopic clusters probably represent synaptic terminals rather than 'en passant' axons.

When 30-50% of all olfactory receptor neurons (ORNs) are made homozygous mutant for acj6⁶ (by using the MARCM technique with Scer\FLP1^ey.PN), Or43a- (glomerulus DA4), Or47a- (glomerulus DM3), Or83c- (glomerulus VA6 and sometimes glomerulus DA3), Or59c- (glomerulus 1), Or71a- (glomerulus VC2) and Gr21a- (glomerulus V) positive ORNs display axon-targetting and ectopic axon clustering defects that are very similar to the phenotypes seen in acj6⁶ mutant flies. Most Or43a-, Or47a-, Or83c-positive acj6⁶ mutant axons do not invade the correct glomeruli and ectopic clusters frequently form far away from the correct glomeruli; in contrast, Or59c-, Or71a- and Gr21a-positive acj6⁶ mutant axons usually include the correct target with ectopic clusters being located adjacent to the correct target. When a 'reverse MARCM' strategy is used in a similar experiment to specifically label homozygous wild type ORNs in a background of 30-50% unlabeled acj6⁶ mutant ORNs, then Or43a-, Or47a- and Or83c-positive wild type axons target correctly (indicative of a cell-autonomous requirement for acj6), whereas Or59c-, Or71a- and Gr21a-positive wild type axons show defective targeting (indicative of a cell non-autonomous requirement for acj6).

When small clones mutant for acj6⁶ are generated (using the MARCM technique and Scer\FLP1^hs.PG), Or43a- (glomerulus DA4), Or47a- (glomerulus DM3) and Or83c- (glomerulus VA6 and sometimes glomerulus DA3) positive olfactory receptor neurons (ORNs) show axon-targeting phenotypes qualitatively similar to those seen when acj6⁶ MARCM/Scer\FLP1^ey.PN clones are made: individual axon branches and terminals are distributed over a large area of the antennal lobe and these defects are cell autonomous. In contrast, Or59c- (glomerulus 1) , Or71a- (glomerulus VC2) and Gr21a- (glomerulus V) positive ORN axons are targeted correctly in MARCM/Scer\FLP1^hs.PG-generated acj6⁶ clones, showing that the requirement for acj6 in these neurons

revealed in MARCM/Scer\FLP1^ey.PN acj6⁶ clones and acj6⁶ mutant flies is cell non-autonomous.

When homozygous somatic clones are made in the lateral projection neurons, no significant change is seen in cell numbers within clones. Clones do exhibit significant dendritic targeting defects. A non-specific accumulation of dendrites, accounting for perhaps a quarter of the total dendritic mass) span a portion of the dorsal side of the antennal lobe. Also the organisation of the glomeruli in this region is disrupted. Outside the dorsal area where non-specific dendritic accumulation is observed, no specific mistargeting to landmark glomeruli or non-landmark glomeruli is seen. Lastly anterodorsal neuroblast clones innervate significantly fewer dorsal landmark glomeruli. Glomeruli VA3 VM2 DM6 are frequently (>80%) weakly innervated. DL1 D and VA1lm are weakly innervated between 20 to 50% of the time. When single cell homozygous clones are made in the DL1 glomerulus, all clones exhibit abnormal dendritic innervation. Only part of DL1 is innervated weakly, and additional dendritic projections are seen in the vicinity of DL1. When single cell clones are made in the anterodorsal projection neurons at laters stages (50-100 hrs ALH), they have diffuse dendrites, which do not target one specific glomerulus. Although the DL1 projection neurons always reach the lateral horn as normal, the dorsal branch of these neurons fail to extend properly, while the lateral branch is largely unaffected. Mutant dorsal branch axons exhibit an 8 fold reduction in the total axon length of the dorsal branch compared to wild-type. Mutant clones have a significantly smaller axonal innervation area than wild-type, leaving the dorsal part of the horn largely innervated.

Homozygous larvae move significantly shorter distances than wild-type larvae in a crawling assay. Homozygous and acj6¹/acj6⁶ adults show reduced activity in a vertical walking assay compared to wild-type adults. Occasional gaps in the lamina plexus are seen in acj6¹/acj6⁶ larvae. Lamina precursor cell proliferation and initial lamina neuron differentiation are wild type. The entire lamina plexus is of irregular thickness in homozygous larvae, generating irregular small breaks. The arborisations and terminals of the L1 and L3 lamina neurons are disorganised and unevenly spaced. In addition, the structure of the synaptic terminals is diffuse and overlaps are seen.

acj6⁶ flies show reduced motility in a "bump assay"; if a bottle of flies is bumped against a bench such that the flies fall to the bottom of the bottle and then the lid is removed, fewer acj6⁶ flies escape in 15 seconds compared to wild-type flies. The amplitudes of receptor potentials recorded from adult olfactory organs in response to ethyl acetate are reduced in homozygotes compared to wild-type flies. Wild-type maxillary palp sensilla can be divided into 3 classes (types 1, 2 and 3), each of which contains a pair of neurons (1A and 1B in type 1, 2A and 2B in type 2 and 3A and 3B in type 3). Each type of neuron has a distinct spectrum of responses to different odours. The 1A neuron is abnormal in homozygous acj6⁶ flies; in some cases type 1 sensilla containing two 1B neurons are found, suggesting that the 1A neuron is transformed into a 1B neuron, while in other cases a neuron that does not respond to any of the tested odours is found alongside a single 1B neuron, suggesting that the 1A neuron has been transformed into this unresponsive neuron. No neurons with the olfactory response spectrum of either 2A or 2B neurons are found in homozygous acj6⁶ flies, instead neurons are found that have a novel spectrum of response to odours unlike any of the wild-type neuronal classes. Sensilla containing this novel "2C" neuron contain a second neuron that produces spontaneous action potentials but does not respond to any of the tested odours. In the type 3 sensillum in homozygous acj6⁶ flies, the 3A neuron appears to be transformed to an unresponsive neuron that is housed alongside a normal 3B neuron.

acj6⁶, pdm3[+]/pdm3^f00828 has abnormal smell perception | recessive | adult stage phenotype

acj6⁶, pdm3[+]/pdm3^f00828 has abnormal neurophysiology | adult stage phenotype

acj6⁶ has antennal lobe glomerulus DL1 | somatic clone phenotype, enhanceable by vvl^UAS.cCa/Scer\GAL4^GH146

acj6⁶ has adult antennal lobe projection neuron DL1 adPN | somatic clone phenotype, enhanceable by vvl^UAS.cCa/Scer\GAL4^GH146

acj6⁶ has antennal lobe glomerulus DL1 | somatic clone phenotype, enhanceable by ct^UAS.cPa/Scer\GAL4^GH146

acj6⁶ has adult antennal lobe projection neuron DL1 adPN | somatic clone phenotype, enhanceable by ct^UAS.cPa/Scer\GAL4^GH146

acj6⁶ has antennal glomerulus DL1 & neuron | somatic clone phenotype, enhanceable by vvl^UAS.cCa/Scer\GAL4^GH146

acj6⁶, pdm3[+]/pdm3^f00828 has adult olfactory receptor neuron Or42a phenotype

Scer\GAL4^GH146, acj6⁶, ct^UAS.cPa has antennal lobe glomerulus VM2 | somatic clone phenotype

Scer\GAL4^GH146, acj6⁶, ct^UAS.cPa has antennal lobe glomerulus DM6 | somatic clone phenotype

Scer\GAL4^GH146, acj6⁶, ct^UAS.cPa has antennal lobe glomerulus DC1 | somatic clone phenotype

Scer\GAL4^GH146, acj6⁶, ct^UAS.cPa, vvl^UAS.cCa has antennal lobe glomerulus DM2 | somatic clone phenotype

Scer\GAL4^GH146, acj6⁶, ct^UAS.cPa, vvl^UAS.cCa has antennal lobe glomerulus DA2 | somatic clone phenotype

Scer\GAL4^GH146, acj6⁶, vvl^UAS.cCa has antennal glomerulus DL1 & neuron | somatic clone phenotype