E17 small intestines were dissected and cross-linked for subsequent ChIP. Whole cell lysates were sonicated and incubated with 6 uL CDX2 antibody (A300-691A, Bethyl Labs.) overnight for immunoprecipitation. ThruPLEX DNA-seq Kit (Rubicon Genomics) was used to prepare libraries, and 75 bp single-end reads were sequenced on an Illumina NextSeq 500 instrument.