Cloning of a Novel Protein of AD Amyloid

Amyloid is the focus of current Alzheimer’s disease (AD) research because it is unique in this disease and accumulates as the core in senile plaques and along the vessel wall in the brain tissue of patients afflicted with AD . The major constituent of amyloid is called ß/A4 – protein and it is derived from a precursor. A recent study demonstrated a-1-antichymotrypsin as an additional component of amyloid, raising the possibility that amyloid might be composed of more than one type of protein. Recently, we have identified a third component of amyloid and propose to study this protein using molecular biological, biochemical, immunological, and cell biological techniques. We call this new protein in the amyloid NAC, signifying new amyloid component. The NAC protein sequences were used to raise antisera. Two antisera raised against the two independent peptides stained amyloid in the core of senile plaques using the PCR technique. A portion of these sequences was used to generate a synthetic gene corresponding to the NAC protein. A full-length MAC c DNA was further isolated using this PCR-generated gene fragment. In the current proposal, we will complete the cDNA cloning of this protein and analyze RNA levels of various tissues. especially brain tissues from both control and AD patients. Furthermore, we will map the gene for this protein in human chromosomes using human hamster hybrid cell lines. If the gene is mapped to chromosomes containing putative AD genes. then fine mapping will be attempted. In parallel!, we will raise antibodies against another portion of NAC for further immunohistochemical and immunochemical analysis of this protein. Probes that are generated will be used to identify the biological function of NAC. Characterization of NAC should shed further light on the amyloidogenes is in AD and might help in finding the etiology of this devastating disease and, finally, a therapeutic strategy.