Mesenchymal Meis2 Controls Whisker Development Independently From Trigeminal Sensory Innervation

The study investigates the role of Meis2 expression in mesenchymal cells derived from the neural crest in whisker development. It finds that Meis2 is crucial for whisker formation and the branching of trigeminal nerves, although whisker development occurs independently of trigeminal sensory innervation. MEIS2 in mesenchymal dermal cells is essential for initiating epithelial placode formation and subsequent dermal condensation. While MEIS2 regulates the expression of the transcription factor Foxd1, which is associated with pre-dermal condensation, the deletion of Foxd1 does not impact whisker development. The findings highlight the early role of mesenchymal MEIS2 in whisker formation, demonstrating that whiskers can develop without sensory innervation or FOXD1 expression.