Complementary DNA for the mouse homolog of the human amyloid beta protein precursor

The human amyloid beta protein is a major component of brain amyloid found in patients with Alzheimer's disease. As an initial step to understand the biological function of its precursor protein, we have isolated cDNA for the mouse homolog of the human beta protein precursor. Comparison of the predicted amino acid sequence with that of human revealed a quite high degree of homology (96.8%), and the calculated evolutionary rate of the mRNA at amino acid substitution site was relatively low (0.1 x 10(-9)/site/year). The mRNA was abundant in brain and kidney, and also detected in other tissues at low level. These results indicated that this protein is highly conserved through mammalian evolution and may be involved in a basic biological process(es).