This pan-neuronal expression of rut AC partially restores olfactory learning in the rut mutant. Several GAL4 enhancer trap lines were selected for local rescue because of their expression patterns. The GAL4 line 201y partially rescues the rut learning defect. Nor do the nonrescuing GAL4 enhancer trap inserts have a negative effect on wild-type flies. Control experiments were conducted with naive wild-type, rut mutant, and potentially rescued rut mutant flies to assure that none of the memory scores were due to changes in shock reactivity or perception of the odorants.
All genotypes avoid electric shocks at similar levels.
Thus, these shock reactivity scores cannot be responsible for the low memory scores. To determine what brain structures are minimally sufficient for olfactory short-term memory, the expression patterns of the rescue and nonrescue GAL4 enhancer trap lines were examined. Serial sections show that the common structure labeled in all rescuing GAL4 lines is specifically the mushroom bodies. Indeed, comparing expression patterns of rescuing and nonrescuing lines indicates that the gamma lobes may be especially important. In contrast to the GAL4 lines used, the rescuing line 247 lacks expression in the median bundle.