Somatic clones of type I neuroblasts expressing atoUAS.cJa under the control of Scer\GAL4αTub84B.PL exhibit symmetric cell divisions (indicating altered cell polarity) and a reduction in cell size in the optic lobe of third instar larvae.
Expression of atoScer\UAS.cJa driven by Scer\GAL4dpp.blk1 leads to neurogenesis (presence of ectopic sensory organ precursors) in third instar larval wing discs.
Clones that express atoScer\UAS.cJa behind the morphogenetic furrow of the eye disc, driven by Scer\GAL4GMR.PF, leads to disorganised clusters with many cells having upregulated adherens junction components.
atoScer\UAS.cJa; Scer\GAL4dpp.blk1 flies have large numbers of ectopic sensory bristles around the A-P compartment boundary of their wings, along with ectopic chordotonal organs.
When expression is driven in the PNS by Scer\GAL4sca.PC, the larval dbd neuron projection is shifted ventrally and from the medial to the intermediate longitudinal fascicle and, in pronounced cases, the dbd-characteristic ventral extension no longer occurs. Late remodelling of the dbd terminal also does not occur. The major CNS axon fascicles are wild type and the larvae hatch.
Expression of atoScer\UAS.cJa under the control of Scer\GAL4ey.PH gives rise to animals in which most of the head and one or both eyes of reduced size are present.
Expression of atoScer\UAS.cJa under the control of Scer\GAL4sca-109-68 produce densely packed arrays of ectopic chordotonal organs. Misexpression of atoScer\UAS.cJa driven by Scer\GAL4h-1J3 results in expansion of lateral chordotonal organ clusters (usually 6-10 neurons instead of 5) but the neurons are of normal morphology.
Expression of atoScer\UAS.cJa under the control of Scer\GAL4ato.3.6 results in excessive branching in the lobula and the medulla as compared to wild type. The organisation of the ato-expressing dorsal cluster, its size and its position are unaffected in third larval instar and adult brains. The number of axons crossing the optic chiasma, but not their morphology, is wild type.
Expression of atoScer\UAS.cJa under the control of Scer\GAL4sca-537.4 slightly induces the formation of multiple dendritic neurons in embryos. A slight increase in the number of chordotonal neurons in the lateral region is also seen. Expression of atoScer\UAS.cJa under the control of Scer\GAL4hs.PB using a 10 minute heat shock just after puparium formation results in ectopic bristles in the wing.
When atoScer\UAS.cJa is driven by Scer\GAL4neur-GAL4-A101, Many of the basiconic and trichoid sensilla of the antenna are converted to a coeloconic lineage, leading to an increase in the latter type of sense organs. Glial cell number is significantly increased and these cells now appear at ectopic positions on the antenna.
When atoScer\UAS.cJa is driven by Scer\GAL4neur-GAL4-A101 a reduction is seen in basiconica and trichoidea and a concomitant increase in coeloconic sensilla. This appears to be a conversion of other sensilla to "ectopic coeloconica".
Flies expressing atoScer\UAS.cJa under the control of Scer\GAL4sca-109-68 have rough eyes, with many ommatidia containing inappropriate complements of photoreceptors and support cells (there can be an increase or a decrease in any specific cell type). This phenotype results from a combination of recruitment and R8 spacing defects. Ommatidial spacing is abnormal and there appear to be fused ommatidia. R8 cells are more dense, frequently juxtaposed (twinned) and unevenly spaced relative to one another. The phenotype is non-autonomous; the presence of supernumerary cells is not always correlated with ectopic ato expression within them. The ommatidia are no longer arranged in straight rows and ectopic photoreceptors infrequently differentiate in the interommatidial spaces. Supernumerary R7 photoreceptors are frequently seen in these flies.
Flies expressing low levels of atoScer\UAS.cJa under the control of Scer\GAL4109 have ectopic bristles on the scutellum, on the dorsocentral notum and wing vein L3. A small number of ectopic chordotonal organs are detected under the cuticle of the scutellum and vein L3. The wild-type chordotonal organs are hyperplastic, consisting of more aligned scolopidia or individual chordotonal unit organs. Flies expressing higher levels of atoScer\UAS.cJa under the control of Scer\GAL4hs.PB show only the ectopic chordotonal organ phenotype. In many places the formation of ectopic chordotonal organs coincides with bristle loss in these flies. In some cases, when expression is driven by Scer\GAL4109, external sense organs are malformed and are associated with scolopales, suggesting an incomplete transformation to chordotonal organs. External sense organs affected in this way include the sternitals of the ventral abdomen, the wing sense organs ACV and TSM1+2 and in extreme cases all other thoracic macrochaetae. Extra sensory organ precursors are seen in the wing discs of flies expressing atoScer\UAS.cJa under the control of Scer\GAL4109. Flies expressing atoScer\UAS.cJa under the control of Scer\GAL4ptc-559.1 are not viable and die as pharate adults with deformed wings and appendages. Ectopic sensory organ precursors are seen in the wing discs of these animals.
Scer\GAL4384-mediated expression causes duplication of the antenna sacculus in a position near to the normal sacculus.
Scer\GAL4hs.PB mediated expression causes a slightly irregular ommatidial pattern: ectopic R8 cells in several ommatidia due to transformation of all 2-3 cells within the R8 equivalence group. Multiple R8 cells are observed in ommatidia that were within the morphogenetic furrow at the time of heat shock.
Fifteen minute heat shock pulse during larval development allows spatially restricted rescue of ommatidia. A row of ommatidia is formed within the pigment cell patch, ommatidia are of variable size. Longer or multiple heat shocks result in pupal death.
When ato is ectopically expressed, large numbers of ectopic chordotonal organs develop.