Heterotopic transplantation of presumptive placodal ectoderm changes the fate of sensory neuron precursors.
The placode-derived cranial sensory neurons of the vestibular and nodose ganglia in avian embryos exhibit differences in neurite growth rate and the duration of neurotrophin-independent survival in vitro that arise prior to gangliogenesis and target contact (Davies, A. M. (1989) Nature 337, 553-555; Vogel, K. S. and Davies, A. M. (1991) Neuron 7, 819-830). To ascertain the state of commitment of presumptive placodal ectoderm to differentiate into neurons of the vestibular or nodose type, we performed heterotopic transplantation of labelled presumptive placodal ectoderm at E1.5 in the chicken embryo. We then assayed transplant-derived neurons for hindbrain innervation patterns, neurite growth and survival at E3.5. We show that presumptive placodal ectoderm is not determined to give rise to neurons of the vestibular or nodose phenotype at E1.5. Explantation of presumptive placodal ectoderm at E1.5 showed that this ectoderm is also not specified to differentiate into neurons at this stage. In addition, we demonstrate that non-neurogenic ectoderm from the trunk can give rise to nodose-type neurons when transplanted heterotopically to the nodose region.
Vogel
K S
KS
Department of Anatomy, St. George's Hospital Medical School, London, UK.
Davies
A M
AM
D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D004475:Ectoderm / Q000166:cytology / Q000502:physiology / Q000637:transplantation*; D004627:Embryonic Induction / Q000502:physiology*; D008856:Microscopy, Fluorescence; D009475:Neurons, Afferent / Q000166:cytology / Q000502:physiology*; D009620:Nodose Ganglion / Q000196:embryology