Molecular profiling of Ctcf hemizygous mouse embryonic fibroblasts: HiC

CTCF is a highly conserved and ubiquitously expressed protein involved in several fundamental processes such as fine-tuning gene expression, imprinting, X-chromosome inactivation and 3D chromatin organisation. To understand the impact of differences in the concentration of CTCF abundance on these processes, we exploit a CTCF hemizygous mouse model with a stable reduction in the concentration of this protein. We derived independent primary lines of mouse embryonic fibroblasts (MEFs) from wildtype and CTCF-hemizygous mouse E13.5 embryos. For three biological replicates, cells were fixed in DMEM containing 2% fresh formaldehyde and incubated at room temperature for 10 min, quenched with 1M glycine for 5 min, and washed twice with ice cold PBS, before being flash-frozen at -80°C. Cross-linked cells were lysed, followed by chromatin HindIII digestion, biotinylataion, ligation, proteinase K treatment, DNA purification, sonication, end repair, biotin pull-down, adapter ligation, and PCR amplification. Pooled indexed libraries were sequenced on an Illumina HiSeq4000 to produce paired-end 150bp reads. On the same MEF lines we have performed RNAseq and ChIPseq for CTCF, H3K4me3 and H3K27ac.