In kncol-1/kncol-3 embryos ap-expressing neurons fail to project their axons into the medial-most Fas2-immunopositive fascicle in the ventral nerve cord. Their commissural (but not lateral) projections are also impaired.
kncol-1 kn+m5 larvae show melanisation of crystal cells after heating at 65[o]C for 10 minutes, as occurs in wild-type larvae.
kncol-1 mutant larvae have no prohemocytes.
Homozygous embryos show a transformation of muscle DA3 to DA2 morphology.
All dorso-lateral muscles are either missing or mis-specified in kncol-1 embryos, while the more dorsal or more ventral muscles are not affected. The most frequently observed defects are DA3>DA2, LL1>DA3 and DO4>DO5 transformations, which indicate changes in progenitor identity. Many myofibres are mis-orientated.
40% of segments in kncol85-GAL4/kncol-1 embryos show a complete DA3>DA2 morphological transformation. In most other segments, the DA3>DA2 muscle maintains thin projections toward the wild type DA3 attachment site, suggesting an incomplete transformation.
kncol-1 mutant embryos have a significant reduction in the number of even-skipped (eve)-expressing neurons in the EL cluster by stage 15, but no difference in the number of other eve-expressing neurons (aCC, RP2, pCC and U/CQ), compared to wild-type controls.
The number of SE2 neurons is normal in kncol-1/kncol-3 mutant animals.
BrdU incorporation in the lymph gland is increased relative to wild-type in mutant third instar larvae and the incorporation becomes distributed throughout the lymph gland. Differentiated cells are found throughout the lymph gland lobe, in contrast to wild type, where they are restricted to the peripheral cortical zone.
In kncol-1 homozygotes and kncol-1/Df(2R)AN293 mutant animals rescued to adult viability by kn+m5 do have plasmatocytes and crystal cells as normal, however when exposed to wasp parasitization a complete lack of lamellocytes is seen (in contrast to the increased numbers seen in wild-type).
Wings veins L3 and L4 are closer to each other in kncol-1/kn1 animals than in wild type and are apposed proximally. The L3-L4 intervein is 66+/-6% smaller than wild type, whereas the anterior margin to L2 and L2-L3 interveins are normal in size. The L4-L5 and L5 to posterior margin interveins are smaller than wild type. The wave of mitosis that normally takes place in each intervein primordium between 15 and 21 hours after puparium formation is specifically absent from the central region of kncol-1/kn1 wings. kncol-1 homozygotes (rescued to adult viability by kn+m5) lack the L3-L4 intervein in the wing. A central larger L3-type vein is present in these flies and only a small, proximal region of wing vein L4 forms. There is a 20% overall reduction in wing size compared to wild type. The L2-L3 intervein is 12+/-5% larger than in wild type. The L4-L5 and L5 to posterior margin interveins are smaller than wild type. The wave of mitosis that normally takes place in each intervein primordium between 15 and 21 hours after puparium formation is specifically absent from the central region of the wings of kncol-1 animals rescued with kn+m5. Loss of wing vein L4 is seen in wings containing homozygous kncol-1 clones that encompass most, if not all, dorsal and ventral cells in the L3-L4 region. Wing vein L4 does form when homozygous dorsal and ventral cells span 3-4 rows of cells along the anterior posterior boundary.
Muscle DA3A/DA4T is missing or (in a few cases) reduced to a thinned muscle. This phenotype is highly penetrant and specific.
Lethality occurs during the late embryonic to first larval instar stage. Homozygous and hemizygous embryos have head defects; the ventral arms are missing and the lateralgraten are reduced. The T-ribs in the floor of the pharynx, and the antennal, maxillary or hypopharyngeal sensory organs are present and a normal pattern of internal sensory structures is seen. The embryos that hatch do not grow and tend to crawl out of the medium, suggesting that they are unable to feed.
Homozygotes and hemizygotes die as embryos or larvae. In a kn1/kncol-1 transheterozygote, the proximal regions of wing veins L3 and L4 are apposed, and the anterior crossvein is missing. When kn+m5 is used to partially rescue the homozygous kncol-1 phenotype, a wing vein phenotype remains. The L3-L4 intervein or anterior crossvein is completely absent, the overall size of the wing and the number of innervated bristles at the anterior margin are unchanged. Wing veins L3 and L4 are apposed and abnormally large, each vein maintaining its identity. The number, ratio and position along the A-P axis of socketed and unsocketed bristles is normal.