Analysis of DNA variations in promoter region of HCNP gene with Alzheimer's disease.

Hippocampal cholinergic neurostimulating peptide (HCNP), which enhances acetylcholine synthesis and induces cholinergic phenotype development of the septohippocampal system, is derived from HCNP precursor protein (HCNPpp), also known as phosphatidylethanolamine binding protein (PEBP) and Raf kinase inhibitor protein (RKIP). Our previous study demonstrated that expression of HCNPpp mRNA was decreased in the hippocampi of autopsied brains of Alzheimer's disease (AD) patients, indicating the association of HCNP with the pathogenesis of AD. To clarify the involvement of gene variations in the promoter region of the gene encoding HCNPpp in this mRNA reduction, we analyzed DNA polymorphisms or mutations within this gene promoter region in AD patients by direct sequencing. The promoter was found to contain a CpG island without a TATA box, an element of housekeeping gene promoters. Moreover, no disease-specific polymorphisms or mutations were identified, suggesting that the decrease of mRNA can be ascribed to transcriptional or posttranscriptional changes in activity.