NeuroD1 reprograms chromatin and transcription factor landscapes to induce the neuronal program

Cell fate specification relies on the action of critical transcription factors that become available at distinct stages of embryonic development. One such factor is NeuroD1, which is essential for eliciting the neuronal development program and possesses the ability to reprogram other cell types into neurons. Given this capacity, it is important to understand its targets and the mechanism underlying neuronal specification. Here, we show that NeuroD1 directly binds regulatory elements of neuronal genes that are developmentally silenced by epigenetic mechanisms. This targeting is sufficient to initiate events that confer transcriptional competence, including reprogramming of transcription factor landscape, conversion of heterochromatin to euchromatin and increased chromatin accessibility, indicating potential pioneer factor ability of NeuroD1. The transcriptional induction of neuronal fate genes is maintained via epigenetic memory despite a transient NeuroD1 induction during neurogenesis. Our study not only reveals the NeuroD1-dependent gene regulatory program driving neurogenesis but also increases our understanding of how cell-fate specification during development involves a concerted action of transcription factors and epigenetic mechanisms. Overall design: 1. Ectopic NeuroD1 was induced for 48 hours (+Dox) in ES cells for checking initiation of neuronal transcriptional program in comparison to uninduced condition (-Dox) 2. ChIP-seq was performed after 24 hours of NeuroD1 induction in ES cells.

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Pataskar A, Jung J, Smialowski P, Noack F, Calegari F, Straub T, Tiwari VK