Replication-Dependent Loss of 5-Kydroxymethylcytosine in Mouse Preimplantation Embryos

摘要

Although DNA methylation is a relatively stable epigenetic modification, global DNA demethylation has been observed in two stages during embryogenesis. One takes place in zygotes, when the paternal genome is preferentially demethylated (/). Despite great efforts in identifying the responsible enzymes, the identity of the putative DNA demethylase has remained elusive (2). Recent demonstration that the Tet (ten eleven translocation) family proteins are capable of converting 5-methylcytosine (5mC) of DNA to 5-hydroxymethylcytosine (5hmC) raises the possibility that Tet proteins might be involved in this process (3, 4).