Identification in rodents and other species of an mRNA homologous to the human beta-amyloid precursor.

The isolation and sequencing of the core peptide (beta-amyloid) found in the plaques of patients with Alzheimer's disease has allowed the identification of a cDNA for the precursor protein. Using a human cDNA clone for this beta-amyloid material, we have identified an homologous mRNA (3.8 kb) in brain tissue obtained from 8 additional species. We have also determined its distribution in 7 brain regions and 12 organs obtained from rodents. A prominent, second mRNA species (2.2 kb) has been identified in rat non-neuronal tissues. The beta-amyloid gene is amply expressed in the brain of all vertebrates tested and in most rodent organs, indicating that it encodes a highly conserved and ubiquitous protein.