Chromatin accessibility assay in Zfp266 Wt and KO cells, in mouse embryonic fibroblasts and at 72 hours of OSKM reprogramming

We used Omnni-ATAC-Sequencing to generate chromatin accessibility maps of the genome in Zfp266 KO and Wt control cells, both in mouse embryonic fibroblasts (MEFs) and at an early stage of reprogramming (72 hours after OSKM induction by the addition of doxycycline). We found distinct loci become more open when Zfp266 is knocked out, so called More Open Regions (MORs) and these regions significantly overlap with B1 SINEs in both MEFs and reprogramming cells. In MEFs, Zfp266 KO MORs are strongly enriched for AP-1 complex transcription factor binding motifs. In reprogramming, we show Zfp266 KO MORs contain motifs for KLF,SOX and OCT transcription factor families centrally enriched in the summit of ATAC peaks, while overlapping B1 SINEs are excluded from the centre of MORs and instead are located adjacent to OSK binding motifs. Overall design: Examination of chromatin accessibility in MEFs and cells that have undergone 72 hours reprogramming in both Zfp266 Wt and Zfp266 KO conditions