Generation of transgenic zebrafish expressing green fluorescent protein under control of zebrafish amyloid precursor...

Amyloid precursor protein (APP) encodes a transmembrane protein that is well established as contributing a crucial role to the etiology of Alzheimer's disease. We have generated germline transgenic zebrafish that express green fluorescent protein (GFP) under control of the endogenous zebrafish appb gene. Expression of GFP by the zebrafish appb promoter requires an enhancer element identified in the first intron of the zebrafish appb gene, with this region exhibiting conservation from zebrafish to human. GFP expression in these transgenic zebrafish recapitulates endogenous appb gene expression as shown by in situ hybridization. We show that GFP is expressed in subregions of brain and in spinal cord, as well as being expressed in the developing vasculature of zebrafish embryos. GFP expression is also developmentally regulated, beginning during the first day of development and then increasing in intensity during later development. In 2.5-month-old young adult transgenic zebrafish, GFP expression was abundantly and widely expressed in the brain. The importance of these transgenic zebrafish lines is that it will be possible to assess the effects of environmental factors, natural products, and therapeutic compounds on APP gene expression during nervous system development, using zebrafish as a model system.