Comparative analysis of neural crest development in the chick and mouse.

A core framework of the gene regulatory network (GRN) governing neural crest (NC) cell development has been generated by integrating separate inputs from diverse model organisms rather than direct comparison. This has limited insights into the diversity of genes in the NC cell GRN and extent of conservation of newly identified transcriptional signatures in cell differentiation and invasion. Here, we address this by leveraging the strengths and accessibility of the avian embryo to precise developmental staging by egg incubation and use an integrated analysis of chick (HH13) and mouse (E9.5) embryo tissue samples collected during NC cell migration into pharyngeal arches 1-2 (PA1 and PA2). We successfully identify a cluster of NC cells containing both mouse and chick cells that share expression of Lmo4, Tfap2B, Sox10, and Twist1, and distinct genes that lack known conserved roles in NC. Importantly, we discovered a cluster of cells exhibiting a conserved transcriptional signature associated with the NC cell migratory wavefront in both mouse and chick, including KAZALD1, BAMBI, DES, and GPC3. We confirm their expression is restricted to leader mouse NCs by multiplexed FISH. Together, these data offer novel insights into the transcriptional programs that underlie NC cell migration and establish the foundation for future comparative functional analyses.