Dev111427 1..6

The role of planar cell polarity (PCP) signalling in neural crest (NC) development is unclear. The PCP dependence of NC cell migration has been reported inXenopus and zebrafish, but NCmigration has not been studied in mammalian PCP mutants. Vangl2 mouse embryos lack PCP signalling and undergo almost complete failure of neural tube closure. Here we show, however, that NC specification, migration and derivative formation occur normally in Vangl2 embryos. The gene family member Vangl1 was not expressed in NC nor ectopically expressed in Vangl2 embryos, and doubly homozygous Vangl1/Vangl2 mutants exhibited normal NC migration. Acute downregulation of Vangl2 in the NC lineage did not prevent NC migration. In vitro, Vangl2 neural tube explants generated emigrating NC cells, as in wild type. Hence, PCP signalling is not essential for NC migration in mammals, in contrast to its essential role in neural tube closure. PCP mutations are thus unlikely to mediate NC-related birth defects in humans.