For c-Jun ChIP, ESCs were fixed with 1% formaldehyde for 15min and then followed by the reaction with 0.125M glycine. Cells were then lysed in ChIP- buffer A (50mM HEPAS-KOH, 140mM NaCl, 1mM EDTA (pH8.0), 10% glycerol, 0.5% NP-40, 0.25% Triton X-100 and 50mM Tris-HCl (pH8.0), and protease inhibitor cocktail for 10min at 4℃. Samples were centrifuged at 1400g for 5min at 4 ℃.Pellets were lysed in ChIP buffer B (1% SDS,50mM Tris-HCl (pH8.0),10mM EDTA and protease inhibitor cocktail) for 5min at 4℃. The DNA was fragmented to 100-500bp by sonication, and then centrifuged at 12000g for 2min. The supernatant was diluted with ChIP IP buffer (0.01%SDS, 1%TritonX-100, 2mM EDTA, 50 mM Tris-HCl (pH8.0), 150mM NaCl and protease inhibitor cocktail). Immunoprecipitation was preformed with 2μg rabbit anti-c-Jun antibody (ab31419) coupled to Dynabeads with proteinA /G overnight at 4 ℃. Beads were washed, eluted and reverse cross-linked. DNA was extracted by phenol/chloroform for sequencing. The ChIP DNA library was constructed following the Illumina ChIP-seq library generation protocol. Briefly, 10ng ChIP DNA was blunt-ended, then a dA tail was added. Illumina genomic adapters with index sequence were ligated to the DNA. The Adaptor-ligated DNA was amplified by PCR for 18 cycles, the resulting DNA libraries were quantified and tested by qPCR with positive primers to assess the quality of the library. The DNA was diluted to 10nM before sequencing. Sequencing on a HiSeq2000 instrument was carried out by BGI (Shenzhen, China).