Reconstruction of the global neural crest gene regulatory network in vivo [single cell]

Precise control of developmental processes is encoded in the genome in the form of gene regulatory networks (GRNs). Such multi-factorial systems are difficult to decode in vertebrates owing to their complex gene hierarchies and transient dynamic molecular interactions. Here we present a genome-wide in vivo reconstruction of the GRN underlying development of neural crest (NC), an emblematic embryonic multipotent cell population. By coupling NC-specific epigenomic and single-cell transcriptome profiling with genome/epigenome engineering in vivo, we identify multiple regulatory layers governing NC ontogeny, including NC-specific enhancers and super-enhancers, novel trans-factors and cis-signatures. Assembling the NC regulome has allowed the comprehensive reverse engineering of the NC-GRN at unprecedented resolution. Furthermore, identification and dissection of divergent upstream combinatorial regulatory codes has afforded new insights into opposing gene circuits t hat define canonical and neural NC fates. Our integrated approach, allowing dissection of cell-type-specific regulatory circuits in vivo, has broad implications for GRN discovery and investigation. Single cell transcriptional and epigenomic profilling of avian neural crest cells isolated from their in vivo context at 6ss and 7ss stages.