Histone H2B ubiquitination mediated chromatin relaxation is essential for the induction of somatic cell reprogramming [RNA-seq]

Chromatin remodeling plays very important role in cell reprogramming, but its underlying mechanism remains poorly understood. Here, we show that RNF20 is highly expressed at the early stage of reprogramming along with the accumulation of H2B ubiquitination at the same stage, and Rnf20 knockout results in the failure of reprogramming at the initial stage but not the other two stages. RNA-seq showed that Rnf20 knockout mainly affects the early stage of cell reprogramming by impairing the transcription of MET-related genes and early pluripotency genes. Importantly, Rnf20 knockout results in a more compacted chromosomes structure in reprogrammable cells, suppressing the recruitment of reprogramming transcription factors to their proper locations on the chromosomes, and finally resulting in the failure of pluripotent gene network establishment. Our results not only uncover a previously unknown function of RNF20-mediated H2B ubiquitination in cell reprogramming, but also provide mechanistic insights into the epigenetic regulation of reprogrammable cells. Overall design: The transcriptome of Rnf20-/- cells and Rnf20+/+ cells at day 3 of OSKM reprogramming