Mice were euthanized, and tissue was harvested immediately, quickly minced, and cross-linked in 1% formaldehyde for 20 min, followed by quenching with 1/20 volume of 2.5 M glycine solution and two washes with PBS. Cell lysates with fragmented chromatin were prepared by probe sonication in ChIP dilution buffer (50mMHEPES, 155mMNaCl, 1.1% Triton X-100, 0.11% sodium deoxycholate, 0.1% SDS, 1mM phenylmethylsulfonyl fluoride [PMSF], and a complete protease inhibitor tablet [pH 7.5]). ChIP was performed using 2-10 µg of antibodies. For ChIP-seq, material from three to four mice was pooled prior to library generation. ChIP DNA was prepared for sequencing according to the amplification protocol provided by Illumina.