Expression of Alzheimer amyloid β-protein precursor gene in neuronal cells

Five forms of Alzheimer amyloid β-protein precursors (APP or BPP) have been found. Among them, APP695 is predominantly found in neuronal cells and may be involved in some neuronal functions. In the present work, we investigated the relationship between the APP expression and the formation of neurites, a typical neuronal morphology, by measuring the amounts of three major APP mRNAs in PC12 cells, using the polymerase chain reaction. In PC12 cells, nerve growth factor which induced a neurite formation, enhanced the expression of APP695. The ratio of APP695 to APP770 increased 2.6-fold after 6 days of treatment. Cyclic AMP also induced a similar morphological change, but did not affect the APP expression pattern. Thus, the neuronal expression of the APP gene is not directly related with neurite formation. We have also identified cis-elements for the neuronal expression of APP gene.