After fertilization, the sperm and oocyte genomes undergo extensive epigenetic reprogramming to form a totipotent zygote. STPG4, also known as GSE (gonad-specific expression), is a maternal factor involved in this process. It plays an important part in the regulation of gametic DNA demethylation by inducing the conversion of the modified genomic base 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC) [].
