CELL-MIGRATION FROM THE TRANSPLANTED OLFACTORY PLACODE IN XENOPUS

The eye vesicle of Xenopus borealis has been replaced with the transpl anted olfactory primordium from Xenopus laevis in an attempt to determ ine whether cells from the transplant could migrate along the regrowin g olfactory nerve and become incorporated into the CNS of the host. Th e use of X. laevis and X. borealis pairs allowed us to distinguish the cells of the host from those of the donor at the cellular level by me ans of the characteristic fluorescent nuclear spots (Q bands) of X. bo realis. Transplantation was performed on pairs of animals at stages 23 /24. The olfactory anlage was readily incorporated into the host, ofte n fusing with the host homolateral organ and inhibiting the regrowth o f the eye vesicle. An olfactory nerve developed from the transplanted organ. In the majority of cases, the nerve reached the diencephalon at the level of entrance of the optic nerve. Along the nerve originating from the transplanted organ we observed a stream of cells with the ch aracteristics of the donor. These cells penetrated the host's CNS and became incorporated into it. The nature of these cells has not been as certained by specific neuronal markers. However, on the basis of their morphology and disposition, the hypothesis suggested is that some of the migrating cells are neurons.