Cells were fixed with 1% formaldehyde and was sonicated in a Bioruptor System (Diagenode, USA). ChIP assay was performed with the Magna Chip Hisens Kit (Millipore,USA) according to manufacturer’s instructions and using the Anti-Dnmt3b antibody-ChIP Grade (Abcam, USA). 10% of samples volume/reaction was kept as controls (input) before immunoprecipitation. ChIP and input samples were processed with the ChIP-Seq DNA sample prep kit (Illumina, USA), following the manufacturer’s instructions. Size-selection was then performed by agarose gel electrophoresis to isolate fragments with size between 200 and 300bp. Afterwards, purified libraries were amplified by PCR and size range was subsequently checked in the Agilent 2100 Bioanalyzer using the High Sensitivity DNA Kit (Agilent, USA). Quantification was performed in the 7500-Real Time PCR System (Applied Biosystems) with the Library Quantification Kit (Kapa Biosystems). After proper dilutions, 4 nM libraries were processed, to obtain pools at a final concentration of 8 pM following the instructions of the Miseq Reagent kit V2. (50 cycles) (Illumina, USA).