dlp1/dlp2 larvae have a normal number of boutons at the neuromuscular junction. Mean active zone area is significantly decreased and the number of active zones per bouton is significantly increased compared to wild type.
The amplitude of the evoked excitatory junctional potential (EJP) is increased compared to wild type at the neuromuscular junction of dlp1/dlp2 larvae. The amplitude and frequency of miniature EJPs is normal. Quantal content is increased.
:dlp1/dlp2 mutants show axon guidance defects. At the third instar larval stage, ~30% of mutants show thickening of the lamina plexus, and >60% show crossovers between ommatidial axon bundles and abnormal photoreceptor process expansion outside the lamina plexus. At the pupal level, 80% of dlp1/dlp2 mutants have brains with irregularities in the R7 and R8 medulla termini and over 20% show medulla cartridge crossover. The differentiation of dlp1/dlp2 photoreceptors is not defective.
Less than 5% of dlp2 mutants survive to adulthood. dlp1/dlp2 embryos from dlp1 germline clone females and dlp2 males show a severe segment polarity defect with denticles covering the ventral surface. dlp1/dlp2 escapers show patterning defects at the anterior margin, with ectopic mechanosensory bristles on both dorsal and ventral surfaces, that are positioned further from the wing margin than bristles in wild type. This phenotype is fully penetrant, but the number of ectopic bristles varies.