Whole DNA methylation on human oocytes retrieved at different maturation stages after superovulation

DNA methylation is the most widely investigated epigeneticmodification associated with the repression of endogenous retrotransposons,the stabilization of X-chromosome inactivation, the centromere function andthe overall regulation of genes expression. By acting as an important molecularmark underlying the parental-specific expression of genes subjected to genomicimprinting, DNA methylation plays a significant role in regulating gametematuration, fertilization, embryo growth and placental function. In fact,maternal and paternal imprinted genes are essential for a normal development.Even if recent studies have shown that complete DNA methylation of someimprinted genes occurs only at metaphase II (MII) stage, immature oocytesare highly methylated. The aim of this work was to compare the whole DNAmethylation profile between human germinal vesicle (GV) oocytes andhuman MII oocytes retrieved after ovarian hyperstimulation, in order to investigatewhether differences in the acquisition of an epigenetic profile should berelated to the meiotic maturation stage.[...