A 1.5kb Psn promoter regulatory sequence (PEPC - Psn endogenous promoter cassette) drives expression of the longer isoform of Psn, mutated to carry an amino acid substitution that is equivalent to a G206A mutation in the orthologous human PSEN1 gene, a variant associated with familial Alzheimer disease.
The vast majority of PsnG206A.PEPC.L flies exhibit neurogenic defects, ranging from mild to severe, manifesting as a rough eye phenotype, wing notching, and abnormal thoracic bristle patterning. A small number of these flies die at the late prepupal stage.
Based on statistical analysis of the age of onset and the severity of the phenotype, the following Psn alleles can be ranked in the following order, from strongest to weakest: PsnL166P.PEPC.L = PsnL173W.PEPC.L = PsnP436Q.PEPC.L = PsnV272A.PEPC.L = PsnL235P.PEPC.L > PsnM146L.PEPC.L = PsnM139V.PEPC.L = PsnH163R.PEPC.L = PsnE280A.PEPC.L = PsnA246E.PEPC.L = PsnG206A.PEPC.L > PsnA79V.PEPC.L = PsnF175S.PEPC.L = PsnE318G.PEPC.L.