Expression of Hsap\APOE^4.Scer\UAS driven by Scer\GAL4^GMR.PFa results in disorganized architecture and degeneration of photoreceptor neurons, resulting in irregular surface morphology and vacuolar structures in the eye in 3-5 day old flies; the rate and extent of degeneration is higher with expression of Hsap\APOE^4.Scer\UAS compared to Hsap\APOE^3.Scer\UAS. Expression of Hsap\APOE^4.Scer\UAS driven by Scer\GAL4^Appl.G1a results in a significant reduction in the number of neurons (measured as fluorescent intensity) in the mushroom bodies and 10 and 40 day old flies show middle-term olfactory memory defects (0-180 minutes after 1 training cycle) and long-term olfactory memory impairments (24hr after 10 spaced conditioning cycles) compared to wild type; the phenotypes are significantly more severe with expression of Hsap\APOE^4.Scer\UAS compared to Hsap\APOE^3.Scer\UAS. Expression of Hsap\APOE^4.Scer\UAS driven by Scer\GAL4^elav-C155 leads to a shortened lifespan compared to controls.

Acute and chronic paraquat treatment in flies with expression of Hsap\APOE^4.Scer\UAS driven by Scer\GAL4^Appl.G1a leads to significant increases in reactive oxygen species levels and to a higher degree of neurodegeneration than untreated controls, and a significant decline in 1hr and 3hr MTM performance with chronic exposure (acute exposure results in improved memory performance in flies expressing Hsap\APOE^4.Scer\UAS).