RES ULT S TET proteins mediate the loss of 5mC in T reg cell–specific regulatory regions during T reg cell development

To examine the dynamic changes of DNA modification during T reg cell differentiation, we sorted cells from male Foxp3–internal ribosome entry site (IRE S)–enhanced GFP (eGFP) reporter mice at sequential stages of their differentiation toward the T reg cell lineage in the thymus and their final maturation in the periphery. In these mice, a cassette encoding IRE S-eGFP had been inserted into the 3′ untranslated region of the Foxp3 gene, generating a bicistronic region encoding both Foxp3 and eGFP under the control of the Foxp3 promoter (Haribhai et al., 2007). DNA was prepared from