A gene trap insertion reveals that amyloid precursor protein expression is a very early event in murine embryogenesis

Although it is known that aberrant processing of amyloid precursor protein (APP) in the adult is associated with Alzheimer's disease, the normal roles of APP in neuronal and embryonic development are not clear yet. As part of a gene trap screen undertaken to identify genes coding for secreted proteins involved in mouse gastrulation, we have obtained a mouse line in which the gene encoding APP is mutated by insertion of the lacZ reporter gene. This study shows that App expression is detected as early as gastrulation. In addition, although widely distributed at later stages, APP expression appears dynamically regulated during development.