Nmnat1 mutant clones in sensory neurons in the adult wing undergo rapid degeneration affecting cell bodies as well as axons.
28 day old Nmnat1 mutant flies containing neuroblast clones exhibit β-axon loss in the mushroom body. γ and α'β neurons are not visible and there is some loss of αβ neurons.
Flies with eyes that are mostly homozygous for Nmnat1 (due to somatic clones induced using Scer\FRT and Scer\FLP1ey.PN) with heterozygous patches are smooth with a normal external morphology. Electroretinogram (ERG) recordings from such eyes belonging to young mutants show reduced depolarization and on/off responses. Transmission electron microscopy of lamina synapses from 1-day-old flies with these clones reveal morphological defects; the laminae are disorganized, with various numbers of photoreceptor terminals per cartridge. The terminals contain a fragmented cytoskeleton and misshapen membrane organelles. In presynaptic terminals, the T-bars are amorphous and less electron dense compared to wild type, but they are surrounded by clusters of normally sized synaptic vesicles. However, the size of the T-bar profile, measured by the width of platforms is significantly reduced compared to wild type.