Tox4 Modulates Cell Fate Reprogramming. Tox4 Modulates Cell Fate Reprogramming

Reprogramming to induced pluripotency induces the switch of somatic cell identity to induced pluripotent stem cells (iPSCs). However, the mediators and mechanisms of reprogramming remain largely unclear. To elucidate the mediators and mechanisms of reprogramming, we used a siRNA mediated knockdown approach for selected candidate genes during the conversion of somatic cells into iPSCs. We identified Tox4 as a novel factor that modulates cell fate, using reprogramming efficiency towards iPSCs as an assay. We found that Tox4 is needed early in reprogramming to efficiently generate early reprogramming intermediates, irrespective of reprogramming conditions used. Tox4 enables proper exogenous reprogramming factor expression and the closing and opening of putative somatic and pluripotency enhancers early during reprogramming, respectively. We show that TOX4 protein assembles into a high molecular form. Moreover, Tox4 is also required for the efficient conversion of fibroblasts towards the neuronal fate, suggesting a broader role of Tox4 in modulating cell fate. Our study reveals Tox4 as a novel transcriptional modulator of cell fate that mediates reprogramming from the somatic state to the pluripotent and neuronal fate. Overall design: Bulk RNA sequencing of Tox4 knockdown and control condition early during reprogramming of mouse fibroblasts towards iPSCs