Visualizing Microaggression in the Developing Embryo: Competition Between the Neural Crest and Endothelial Cells

Neural crest and endothelial cell migration events shape critical neural, skeletal and vascular structures in the developing vertebrate head. Yet, the dynamic interplay of these two cell populations has remained unclear due to a lack of in vivo imaging tools. Here, we use dynamic in vivo imaging to simultaneously observe the individual behaviors of fluorescently marked cranial neural crest cells within Tie1 transgenic quail embryos that express H2B‐EYFP in all endothelial cells. Time‐lapse recordings show that cranial neural crest and endothelial cells share common migratory pathways, physically interact, and may move in opposing directions to reach distinct targets. We use cell tracking and quantitative analyses of cell trajectories to characterize the sequence of cell interactions and associated dynamic parameters. To understand the molecular underpinnings of this complex ballet, we examine the expression patterns and functional role of anti‐angiogenic factors expressed by lead neural crest cells using multiplexed fluorescence in‐situ hybridization and a gain‐ and loss‐of‐function approach. Together, our results offer a unique view of early neural and vascular patterning and a model mechanism for cell competition within the developing vertebrate embryo. Support or Funding Information Mary C. McKinney 1 and Paul M. Kulesa 1,2 1 Stowers Institute for Medical Research and 2 University of Kansas School of Medicine, Department of Anatomy and Cell Biology