Chromatin was prepared from the NB490 cell line using the truChIP Chromatin Shearing Reagent Kit (Covaris;520154). Chromatin was sheared in 1 mL millitubes (Covaris;520135) using a Covaris S200 (5% duty cycle, intensity of 4, 200 cycles per burst, for 8 minutes) to obtain chromatin fragments 100 ? 700 base-pairs in length. 50 ug of fragmented chromatin was incubated overnight with 2.5 uL of rabbit anti-PDX1 antibody (Millipore;07-696). Complexes were isolated using 50 uL of Dynabeads (Invitrogen;10004D) previously blocked with BSA (1 mg/mL). 2 ng of immuno-precipitated DNA was prepared as a standard Illumina library using the ThruPLEX DNA-seq Kit (Rubicon), according to manufacturer?s protocol. Samples were PCR-amplified and pooled. Final libraries were checked for quality and quantity by TapeStation (Agilent) and qPCR using Kapa?s library quantification kit for Illumina Sequencing platforms (Kapa Biosystems;KK4835). They were clustered on the cBot (Illumina) and sequenced 2 samples per lane on a 50-cycle single-end on a HiSeq 2000 in High Output mode using version 3 reagents.