Can the rDNA methylation pattern be used as a marker for Alzheimer's disease?
BACKGROUND
Differential methylation activity of the human rDNA in Alzheimer's disease (AD) patients has been demonstrated by classic cytogenetic tools, indicating a decrease in rRNA gene expression. Methylation of CpGs is an important epigenetic mechanism involved in gene expression repression of tandem repeating genes during ageing. Thus, rDNA specific methylation pattern could be involved in AD and be used as a marker of the disease or of its progression.


METHODS
The methylation pattern of three rDNA regions, including the promoter, 18S, and 28S, was investigated with the use of restriction endonucleases sensitive to methylation and Southern blotting from DNA extracted from total peripheral blood cells of 28 AD patients and 28 elderly and young controls.


RESULTS
We did not find a significant divergence in the methylation pattern of the studied regions and in the relative amount of rDNA methylated copies among the individuals' groups.


CONCLUSIONS
No differential methylation pattern of rDNA genes was observed in total peripheral blood cells in aged and AD subjects by the methodology used.
Sperança
Márcia Aparecida
MA
Disciplina de Biologia Molecular, Marília Medical School, Marília, SP, Brazil. speranca@famema.br
Batista
Lisandra Mesquita
LM
Lourenço
Ricardo da Silva
Rda S
Tavares
Wagner Malagó
WM
Bertolucci
Paulo Henrique Ferreira
PH
Rigolin
Valdeci de Oliveira Santos
Vde O
Payão
Spencer Luiz Marques
SL
Smith
Marília de Arruda Cardoso
Mde A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000235:genetics*; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000235:genetics*; D015139:Blotting, Southern; D016022:Case-Control Studies; D019175:DNA Methylation; D004275:DNA, Ribosomal / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D006801:Humans; D008297:Male; D008875:Middle Aged; D011401:Promoter Regions, Genetic; D012337:RNA, Ribosomal, 18S / Q000235:genetics*; D012339:RNA, Ribosomal, 28S / Q000235:genetics*
D004275:DNA, Ribosomal; D012337:RNA, Ribosomal, 18S; D012339:RNA, Ribosomal, 28S