Altered expressions and DNA methylation of imprinted genes in chromosome 7 in brain of mouse offspring conceived from in vitro maturation

ObjectivesThe aim of this research was to investigate the effects of in vitro maturation (IVM) on the expression of imprinted genes in offspring, and to identify possible regulatory mechanisms for these genes.ResultsBy using an IVM mouse model, mRNA expression of H19 was found down-regulated and Kcnq1ot1 was up-regulated in brains of IVM offspring. Of the differentially methylated regions (DMRs) of H19, CpG island 3 was found to have higher DNA methylation levels in IVM group compared with the control group; in contrast, Kcnq1ot1 showed a significant reduction in DNA methylation in IVM mice by using the bisulfite sequence PCR and pyrosequencing. However, Igf2 and Snrpn showed no significant differences in expression of mRNA or DNA methylation levels between the IVM and control groups. In conclusion, IVM could affect the expression of imprinted genes in the brains of IVM offspring, which could be induced by DNA methylation alterations.

► We use mouse model to detect the epigenetic inheritance of IVM on offspring.
► We examine changes of imprinted genes homologous to human in IVM offspring brains.
► IVM of oocyte could affect the expressions of some imprinted genes in brain of the offspring by regulating their DNA methylation.
► H19 expressed lower in IVM offspring with the up-regulated methylation of the CpG island 3 while Kcnq1ot1 expressed higher in IVM offspring with the down-regulated methylation of the KvDMR.