2.13. Chromatin immunoprecipitation (ChIP) analysis

ChIP assays to validate JunB binding at TGFB1 promoter were performed using Hepa‐1c1c7 cell lysates and an EZ‐ChIP Kit (17‐371, Merck‐Millipore, Burlington, MA, USA) with α‐JunB (#3753, CST) or normal rabbit IgG (#2729, CST). Briefly, formaldehyde‐cross‐linked cells were lysed and sonicated to prepare genomic DNA fragments (200‐500 bp). For each assay, 4 µg of antibody was used to immunoprecipitate 40 µg of input chromatin. Immune complexes were recovered using 30 µL of resuspended protein A/G agarose. After washing, the DNA was de‐crosslinked and eluted, as described in the manufacturer's instructions. qPCR was performed in a 7500 Fast Thermal Cycler (Life Technologies, Carlsbad, CA, USA), using the ChIP primers listed in Supplementary Table S3.