TET2 catalyzes active DNA demethylation of the Sry promoter and enhances its expression

SRY (Sex determining region on Y) is master regulator of male sex determination in eutherian mammal. In mice, Sry is expressed in embryonic gonadal somatic cells in a developmental stage-specific manner. DNA methylation plays a key role in the regulation of developmental genes. It was demonstrated that the CpG sites of Sry promoter undergoes demethylation in embryonic gonadal somatic cells at the sex-determining period. However, its molecular mechanism and in vivo significance remain to be elucidated. DNA demethylation pathway is classified into two types: passive and active demethylation pathways. Here, we report that CpG sites of Sry promoter is actively demethylated during gonadal development. We also demonstrated that TET2 play a fundamental role in the demethylation of Sry. In Tet2-deficient mice, 5-hydroxymethylcytosine (5hmC), an intermediate of active DNA demethylation pathway, was abolished from Sry promoter. Furthermore, Tet2 deficiency diminished Sry expression in embryonic gonads at the sex-determining period. Finally, Tet2 deficiency enhanced sex reversal phenotype of Jmjd1a-deficient mice. Our data demonstrate that Sry expression is positively controlled by an epigenetic mechanism thorough TET2-mediated DNA demethylation.