Early steps in neural development.
We studied early neurulation events in vitro by transplanting quail Hensen's node, central prenodal regions (before the nodus as such develops), or upper layer parts of it on the not yet definitively committed upper layer of chicken anti-sickle regions (of unincubated blastoderms), eventually associated with central blastoderm fragments. We could demonstrate by this quail-chicken chimera technique that after the appearance of a pronounced thickening of the chicken upper layer by the early inductive effect of neighboring endophyll, a floor plate forms by insertion of Hensen's node-derived quail cells into the median part of the groove. This favors, at an early stage, the floor plate "allocation" model that postulates a common origin for notochord and median floor plate cells from the vertebrate's secondary major organizer (Hensen's node in this case). A comparison is made with results obtained after transplantation of similar Hensen's nodes in isolated chicken endophyll walls or with previously obtained results after the use of the grafting procedure in the endophyll walls of whole chicken blastoderms.
University of Antwerp, Laboratory of Human Anatomy and Embryology, B-2020 Antwerpen, Belgium. marc.callebaut@ua.ac.be
Marc
M
Callebaut
Emmy
E
Van Nueten
Hanalie
H
Van Passel
Fernand
F
Harrisson
Hilde
H
Bortier
D000818:Animals; D001756:Blastoderm / Q000637:transplantation*; D036703:Blastula / Q000166:cytology / Q000201:enzymology / Q000637:transplantation; D002454:Cell Differentiation; D002642:Chick Embryo; D002645:Chickens; D002678:Chimera / Q000196:embryology*; D005321:Extraembryonic Membranes / Q000166:cytology / Q000196:embryology / Q000637:transplantation; D005855:Germ Layers / Q000166:cytology / Q000201:enzymology / Q000637:transplantation; D066298:In Vitro Techniques; D008954:Models, Biological; D009420:Nervous System / Q000166:cytology / Q000196:embryology*; D009672:Notochord / Q000166:cytology / Q000196:embryology / Q000637:transplantation; D011784:Quail; D014183:Transplantation, Heterologous