Mutant pupae placed at a semi-permissive temperature at the time of division of pI (sensory organ precursor) cells in the notum show 3.6% pIIa-to-pIIb cell fate transformation.
Mutant male first instar larvae raised at 25[o]C show a 70% reduction in the number of hub cells in the gonad compared to controls.
The number of corpora cardiaca cells is normal in mutant embryos raised continuously at 18[o]C, but is quadrupled in mutant embryos raised continuously at 29[o]C. Temperature shift experiments suggest that Dl function is required from the end of embryonic stage 10 to the beginning of stage 11 to regulate corpora cardiaca cell number.
Culturing Dl6B/DlRF animals at 18[o]C until the early second instar and then shifting to 25[o]C allows some animals to survive to the late third instar. These late third instar larvae have either no lamina or a very incomplete lamina, and have a smaller medulla complex than normal. At the late second-instar, these animals have a relatively normal neuroepithelium in the outer proliferation center, however, the neuroepithelial cells are partially lost by the mid-third instar. Medulla neuroblasts are generated prematurely during early to mid-third instar in these animals, leading to premature medulla neurogenesis (very few medulla neuroblasts are seen at the late-third instar).
In Dl6B/DlRF flies at the permissive temperature of `8[o]C, border cells migrate to reach the oocyte at stage 10. Following incubation of Dl6B/DlRF flies at the non-permissive temperature of 32[o][C overnight, border cells fail to migrate in 12 out of 72 stages 10 egg chambers examined, even though the clusters form.
In DlRF/+ flies shifted to the non-permissive temperaturex, sensory organ precursors in wing disc cells at the time puparium formation have significantly shorter filopodia than wild-type. (x maintained at 18oC and shifted to 30oC 21 hours before fixation).
Dl9P/DlRF animals shifted to the nonpermissive temperature during the early pupal stage develop double shaft bristles.
DlRF/Dl6B animals exposed to the restrictive temperature during the third larval instar and pupal periods develop shortened legs. The tarsal segments are particularly reduced and have seemingly disappeared, but the tarsal apical bristles are still present, and sometimes remnants of joint structures are also visible.
DlA326.2F3/DlRF flies show heat sensitive increases in the severity of Dl mutant wing venation phenotypes. At 18oC the wing veins show mild deltas. Flies pulsed for 8 hours at times equivalent to 20 to 30 hours APF at 250C, display thickened veins and marginal deltas larger than those of animals raised at 18oC.
Homozygous clones including dorsal and ventral clones cause extensive wing scalloping. Clones in the ventral compartment cause small nicks or loss of margin sensory elements. Clones in the dorsal compartment cause only loss of sensory elements.
Clusters of R8 cells develop in DlRF/Dl6B or DlRF/Dl9P flies raised at the restrictive temperature. The clusters are not randomly arranged, but are based on the original R8 array. Extra R8 cells are produced in Nl1N-ts1 DlRF/Dl6B double mutants, although the number of extra R8 cells produced is somewhat reduced compared to Nl1N-ts1 single mutants.
Homozygous third instar larvae raised at 32oC for 5 hours give rise to eye discs with clusters containing 10 to 15 disorganised cells in contrast to the 5 cells per cluster seen in wild-type flies. Eye discs from heat pulsed third instar larvae that are then incubated at the permissive temperature for 24 hours contain successive rows of irregularly spaced photoreceptor clusters with large gaps between each row. Dl6B/DlRF flies show a temperature-sensitive phenotype. At 18oC (permissive temperature) flies have a mild delta phenotype. Dl6B/DlRF larvae raised at 32oC for 5 hours give rise to eye discs with clusters containing extra cells compared to wild-type. These extra cells develop as photoreceptors. Adult flies derived from Dl6B/DlRF larvae heat pulsed 24 hours before puparium formation have a dorsal-ventral 'scar' on the eye, at the approximate position of the furrow during the heat pulse. This region contains a disorganised array of rhabdomeres, many of which are fused or misshapen. Extensive multiplication of cone cells is also seen in this region. Posterior to the scar, clusters contain excess outer photoreceptors and mild multiplication of cone cells is also seen. Posterior to this region, there is a narrow band of cone cell loss, and clusters contain the correct number and type of photoreceptors. The latticework in eye discs of Dl6B/DlRF pupae heat pulse from 11-18 hours after puparium formation (APF) appears to be composed almost entirely of bristles, with a loss of tertiary and secondary pigment cells. This gives rise to adult flies with rough eyes containing a large number of bristles. Temperature shifts for 5 hours between 34-44 hours APF results in interommatidial bristle loss and an increase in the number of primary pigment cells.
Homozygous females are fertile when raised to eclosion and maintained at 18oC, however they become sterile when shifted to 29oC after eclosion. Sterility has two causes, reduction in egg laying, and reduction in hatch rate of any eggs that are laid. Failure of stalk formation between germaria and stage 1 egg chambers is evident, with follicle cell epithelia 2 or 3 cells thick appearing in place of stalks, which later degenerate if 29oC conditions are maintained to 72hr, resulting in the formation of tubular follicle cells surrounding multiple oocytes and nurse cells containing necrotic nuclei. Few egg chambers develop past stage 9. For those eggs that are laid development arrests multiphasically, with defects including failure of fertilization, distorted body axes and neural hypertrophy.
Microchaetae multiplication results from heat pulses 7 to 24 hours after puparium formation, while microchaetae deletion results from heat pulses 24 to 47 hours after puparium formation. Macrochaetae multiplication at high levels results from heat pulses 0 to 5 hours after puparium formation, and later heat pulses can delete macrochaetae.