Cranial neural crest cells form corridors prefiguring sensory neuroblast migration.
The majority of cranial sensory neurons originate in placodes in the surface ectoderm, migrating to form ganglia that connect to the central nervous system (CNS). Interactions between inward-migrating sensory neuroblasts and emigrant cranial neural crest cells (NCCs) play a role in coordinating this process, but how the relationship between these two cell populations is established is not clear. Here, we demonstrate that NCCs generate corridors delineating the path of migratory neuroblasts between the placode and CNS in both chick and mouse. In vitro analysis shows that NCCs are not essential for neuroblast migration, yet act as a superior substrate to mesoderm, suggesting provision of a corridor through a less-permissive mesodermal territory. Early organisation of NCC corridors occurs prior to sensory neurogenesis and can be recapitulated in vitro; however, NCC extension to the placode requires placodal neurogenesis, demonstrating reciprocal interactions. Together, our data indicate that NCC corridors impose physical organisation for precise ganglion formation and connection to the CNS, providing a local environment to enclose migrating neuroblasts and axonal processes as they migrate through a non-neural territory.
Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, UK.
Sabine
S
Freter
Stephen J
SJ
Fleenor
Rasmus
R
Freter
Karen J
KJ
Liu
Jo
J
Begbie
D000818:Animals; D002465:Cell Movement / Q000502:physiology*; D002642:Chick Embryo; D017950:Ganglia, Sensory / Q000166:cytology / Q000196:embryology*; D017403:In Situ Hybridization; D051379:Mice; D018613:Microscopy, Confocal; D009432:Neural Crest / Q000502:physiology*; D058953:Neural Stem Cells / Q000502:physiology*; D011984:Sensory Receptor Cells / Q000502:physiology*; D012886:Skull / Q000166:cytology / Q000196:embryology*
Cranial sensory ganglia; Neural crest; Placode