Double RNA Interference of DNMT3b and DNMT1 Enhances DNA Demethylation and Gene Reactivation

摘要: Small interfering RNAs (siRNAs) are newly identified molecules shown to silence genes via targeted mRNA degradation. In this study, we used specific siRNAs as a tool probe the relationship between two DNA methyltransferase genes, DNMT3b and DNMT1 , in maintenance of methylation patterns genome. Levels or mRNAs proteins were markedly decreased (up 80%) on transfecting these into ovarian cancer cell line CP70. The resulting RNA interference showed differential effects demethylation gene reactivation treated cells. siRNA treatment led partial removal from three inactive promoter CpG islands, TWIST RASSF1A HIN-1 restored expression genes. This epigenetic alteration appeared less effective cells transfected with siRNA. However, combined greatly enhanced effect, producing 7–15-fold increases their expression. We also microarray approach examine 8640 island loci CP70 had greater effect 241 methylated selected repetitive sequences than that single treatment. Our data thus suggest whereas plays key role maintenance, DNMT 3b may act an accessory support function study shows is powerful for interrogating mechanisms normal pathological genomes.