Cross-linking was achieved by the addition of a formaldehyde solution directly to the culture medium to a final concentration of 1%.  Cross-linked complexes suitable for ChIP studies were prepared.  Duplicate samples for each of vehicle or activin A treatment group consisted of pooled samples from three 15 cm plates.  Target-specific antibodies were added to enrich for either SMAD2/3-, FLAG-FOXL2- or H3K27ac-bound complexes.  Antibody-bound complexes were enriched with Protein-A or Protein-G magnetic DYNA beads. Sequencing libraries appropriate for Illumina platforms were prepared for ChIP DNA fragments using NEXTFlex DNA sequencing kits (Bioo Scientific, Austin, TX). Briefly, fragments were blunted using the Klenow fragment followed by the addition of 3'-overhangs and ligation of barcoded adapters, with intervening cleanup steps with magnetic beads/PEG. After PCR amplification with adapter-specific primers, 300-400 bp fragments were size-selected by differential PEG precipitation onto magnetic beads. ChIP-seq libraries were sequenced for 51 cycles to a depth of 20 million reads on an Illumina HiSeq2500 sequencer using single-end 50 bp reads.