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 V272A mutation in the orthologous human PSEN1 gene, a variant associated with familial Alzheimer disease.
PsnV272A.PEPC.L flies exhibit decreased viability in prepupal, pupal, pharate adult and adult stages. In addition, those flies that do survive to adulthood exhibit severe neurogenic defects such as a roughened eye phenotype with supernumerary photoreceptor cells, wing notching, and abnormal thoracic bristle patterning (including duplicated dorsoscutellar macrochaeta).
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.