Dev117507 2014..2025

Neural crest (NC) cell migration is crucial to the formation of peripheral tissues during vertebrate development. However, howNCcells respond to different microenvironments to maintain persistence of direction and cohesion in multicellular streams remains unclear. To address this, we profiled eight subregions of a typical cranial NC cell migratory stream. Hierarchical clustering showed significant differences in the expression profilesof the lead threesubregionscomparedwithnewlyemergedcells. Multiplexed imagingofmRNAexpressionusing fluorescenthybridization chain reaction (HCR) quantitatively confirmed the expression profiles of lead cells. Computationalmodeling predicted that a small fraction of lead cells that detect directional information is optimal for successful stream migration. Single-cell profiling then revealed a unique molecular signature that is consistent and stable over time in a subset of lead cells within the most advanced portion of the migratory front, which we term trailblazers.Model simulations that forced a lead cell behavior in the trailing subpopulation predicted cell bunching near themigratory domain entrance. Misexpression of the trailblazer molecular signature by perturbation of two upstream transcription factors agreed with the in silico prediction and showed alterations to NC cell migration distance and stream shape. These data are the first to characterize themolecular diversity within an NC cell migratory stream and offer insights into how molecular patterns are transduced into cell behaviors.