BETA-A4-AMYLOID PROTEIN-PRECURSOR MESSENGER-RNA ISOFORMS WITHOUT EXON-15 ARE UBIQUITOUSLY EXPRESSED IN RAT-TISSUES INCLUDING BRAIN, BUT NOT IN NEURONS

Abstract

The beta A4-amyloid protein precursor (APP), the source of the beta A4-amyloid deposits found in Alzheimer brains, constitutes a family of transmembrane glycoproteins generated by alternative splicing. While exon 7 and exon 8 are well known to be alternatively spliced, APP mRNA isoforms without exon 15 were only recently identified in leukocytes and rat brain microglial cells and therefore denoted as L-APP mRNAs. In order to perform a detailed analysis of individual L-APP mRNA isoforms in perfused rat tissues, we developed a quantitative polymerase chain reaction assay from reverse transcribed RNA allowing us to analyze the alternatively spliced region in between exon 6 and 16. In all periph..