Quantification of presenilin-1 mRNA in Alzheimer's disease brains

The presenilin-1 (PS-1) gene on chromosome 14 carries mutations which cosegregate with early-onset familial Alzheimer's disease, We quantified PS-1 mRNA in post-mortem mid-temporal and superior frontal cortices from 14 Alzheimer's disease subjects, 9 non-demented controls and 5 subjects with other neurological diseases using solution hybridisation-RNase protection assay, APP and APLP2 mRNAs had previously been quantified in these samples (Johnston et al, (1996) Mel. Brain Res., in press) and subjects were apolipoprotein E (APOE) genotyped, There mere no significant differences between PS-1 mRNA levels per pg total RNA in mid-temporal or superior frontal cortices of the Alzheimer's disease subjects, compared to controls, PS-1 mRNA levels corresponded to 10% of total APP and 30% of APLP2 mRNA levels, and were not significantly affected by age, post-mortem delay, tissue pH, or APOE genotype, PS-1 mRNA showed significant positive correlations with APP and APLP2 mRNA levels in mid-temporal cortex and with APP mRNA in superior frontal cortex, This may reflect a co-regulation of the expression of these genes, or the fact that they are expressed in similar neuronal populations.