A gene regulatory network for neural induction
During early vertebrate development, signals from a special region of the embryo, the organizer, can re-direct the fate of non-neural ectoderm cells to form a complete, patterned nervous system. The process has generally been imagined as the result of a single signaling event, causing a simple switch. Here we undertake a comprehensive analysis, in very fine time-course, of the events following exposure of ectoderm to signals from the organizer. Using transcriptomics and epigenomics we generate a Gene Regulatory Network comprising 175 transcriptional regulators and 5,614 predicted interactions between them, with temporal dynamics from initial exposure to the signals to expression of mature neural plate markers. Using in situ hybridization and single-cell RNA-sequencing and reporter assays we show that neural induction by a grafted organizer mimics normal neural plate development. The study is accompanied by a comprehensive resource including information about conservation of the predicted enhancers in different vertebrate systems.