AGE-RELATED-CHANGES IN GENE-EXPRESSION IN THE RAT-BRAIN REVEALED BY DIFFERENTIAL DISPLAY

We have used the polymerase chain reaction (PCR)-based technique of di fferential display to analyse changes in gene expression during ageing of the rat brain. In this approach we have compared three young adult (6 months) with three old adult (20 months) animals. RNA preparations from the homogenised brains were subjected to reverse transcriptase ( RT)-PCR using 36 different combinations of primer pairs. Any PCR produ ct which was consistently found to be more prominent in the three youn g brains compared to the three old brains, and vice versa, was scored as potentially representing a gene which was differentially expressed during the ageing of this tissue. Out of a possible 2000+ PCR products we identified 44 that might represent genes that exhibit differential expression during ageing of the rat brain. An initial screen of these fragments, by Southern-blotting the PCR products and hybridising them with cDNA probes derived from either young or old brain RNA preparati ons, indicated that 40% of them represented genes that were differenti ally expressed. This approach is likely to prove invaluable for identi fying cohorts of genes that show differential expression during the ag eing process.