Murine BAT was collected immediately after euthanasia. It was 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 ice-cold PBS. Chromatin fragmentation was performed by sonication in ChIP SDS lysis buffer (50 mM HEPES, 1% SDS, 10 mM EDTA, pH 7.5) using probe sonication. Proteins were immunoprecipitated in ChIP dilution buffer (50 mM HEPES, 155 mM NaCl, 1.1% Triton X-100, 0.11% sodium-deoxycholate, complete protease inhibitor tablet, pH 7.5). Crosslinking was reversed overnight at 65 °C in elution buffer (50 mM Tris-HCL, 10 mM EDTA, 1% SDS, pH 8.0) and DNA was isolated using phenol/chloroform/isoamyl alcohol. Precipitated DNA was analysed by quantitative PCR. ChIP DNA was prepared for sequencing according to the amplification protocol provided by Illumina.