Dll17/Dll3 mutant larvae show a significantly impaired behavioural response to an attractive odorant (EtOAc). Some larvae show dorsal organ malformations but there appears to be no correlation between the larvae with cuticular defects and those with olfactory impairment. Motor activity appears normal, and allowing more time for the larva to respond (10 minutes rather than 5 minutes) does not change the response indices.
Heterozygous Dll17 mutant larvae show a significantly impaired response to an attractive odorant (EtOAc). No malformations are seen in in the cuticular components of the dorsal organ.
Heterozygous Dll17 mutant embryos have fewer neurons and fewer support cells in the dorsal organ (DO) and terminal organ than wild type animals. No cell death is seen (TUNEL staining) and the remaining neurons exhibit aberrant morphologies. The DO dendrites are loosely associated rather than tightly bundled.
Large minute clones of Dll17 result in almost all portions of distiproboscis being eliminated. The mediproboscis is not eliminated by these clones.
The basal capsule of the arista is almost normal in heterozygous flies.
Dll3/Dll17 animals die as pharate adults. They show truncations of the antenna, such as deletion of antennal segment 3 and the arista. A complete loss of the tarsal segments and shortening of both the femur and tibia is seen in the legs.
Dll17 somatic clones do not develop anal plates in males, or dorsal anal plates in females. Clones do not show any detectable alterations in the male external genitalia. Clones do not affect the development of the female ventral anal plates.
Dll17 somatic clones produce areas of defective cuticle and are unable to form anal plates.
The distribution of homozygous clones along the proximodistal axis of the leg differs from the distribution of control clones; the ratio of distal-to-proximal clones is 2:1 for control clones and 1:4 for homozygous Dll17 clones, suggesting that homozygous Dll17 clones are lost distally. Homozygous clones in the tarsal segments segregate out of the surrounding wild-type imaginal disc epithelium. Vesicles of homozygous Dll17 tissue are sometimes seen inside the tarsal segments of the legs of adult flies.
Homozygous clones can be recovered in the dorsal femur when they are generated at any stage in development (from embryo to mid-third instar larva), although early in development their frequency is reduced compared to wild-type clones. When the leg is composed almost entirely of Dll17 tissue then the region more distal to the coxa is represented by only a small stump of tissue. The characteristic hairs and bristles found at the wing margin are deleted in homozygous clones at the margin. The effect of these clones is autonomous.
Homozygous clones induced in the leg discs do not proliferate. Homozygous clones induced in the leg during the first and second larval instar stages are only found in the pleural and coxa regions and produce no morphological abnormalities. Homozygous clones induced in the leg during the third larval instar stage are frequently seen in the distal regions of the leg. The majority of clones in the trochanter and tibia-tarsus region form vesicles that invaginate inside the appendage. These clones often contain bristles and trichomes that do not resemble those in the vicinity of the clone. Clones in the femur and proximal tibia contain bristles without bracts. Homozygous clones induced in the antenna during the first larval instar stage are able to differentiate the aI antennal segment and a small part of the aII antennal segment, but are unable to form the rest of the aII segment, segment aIII or the arista. Homozygous clones induced in the antenna during the third larval instar stage tend to form vesicles that are separated from the surrounding tissue in segments aII and aIII. Clones in the arista often differentiate bracted bristles, suggesting an antennal to leg transformation. Homozygous clones induced in the wing during the larval stage affect the wing margin; the triple row of bristles in the anterior compartment and the double row of long hairs in the posterior compartment are eliminated. Clones away from the margin often affect vein differentiation in the vicinity of the margin. This affect can be nonautonomous as wild-type cells in the vicinity of the clone are often affected. The clones develop socketed bristles in the posterior compartment and also develop a halo of pigment.
Dll null mutant embryos produced both leg and imaginal discs following in vivo culture.
Embryos have normal mouth hooks and ventral organs, but missing an average of 5 cirri from the anterior row and 7 cirri from the posterior row. Also the ventral organ often includes extra papillae of unknown origin.
Wnt5 expression in head and thoracic segments is absent in embryos presumed to be homozygous for this allele.
Greatly reduced femur and tibia, associated with normal trochanter and coxa.