DNA methylation, ageing and ribosomal genes activity

DNA methylation is an epigenetic mechanism controlling of gene expression. We studied the effect of a demethylation agent 5-azacytidine, on ribosomal gene activity observed by Nucleolus Staining Giemsa in the chromosomes of e ight Alzheimer's disease patients, eight elderly healthy individuals and ei ght young healthy controls. Metaphase cells were obtained from lymphocyte c ultures. All the acrocentric chromosome pairs were analyzed using G banding followed by Nucleolus Staining Giemsa banding in the same cell. The Alzhei mer's disease patients and elderly healthy control did not show a variation in the transcriptional activity of ribosomal genes with or without 5-azacy tidine treatment, whereas the young control group showed an increase in thi s activity with the treatment.