Cells were harvested from mice that were approximately 3-4 weeks old. Lymph nodes and spleen cells were sorted based on CD4, CD25,GITR and Fr4 or CD4, CD25, Foxp3-GFP. Cells were fixed with formaldehyde, nuclei were extracted and sonicated. For RNA-seq total RNA was extracted using Quiagen's RNeasy Kit and TRIzol reagent ChIP DNA was prepared for high throughput sequencing library using Accel-NGS 2S Plus DNA library kit ChIP-seq and HiChIP with Illumina Hiseq4000, Illumina HiSeq 2500 single-end 50bp sequencing platform for RNA-seq