TY - JOUR
T1 - State of commitment of prospective neural plate and prospective mesoderm in late gastrula/early neurula stages of avian embryos
AU - Garcia-Martinez, Virginio
AU - Darnell, Diana K.
AU - Lopez-Sanchez, Carmen
AU - Sosic, Drazen
AU - Olson, Eric N.
AU - Schoenwolf, Gary C.
N1 - Funding Information:
We gratefully acknowledge the technical assistance of Arlene Carillo. The Hoxb-1 cDNA was graciously provided by R. Krum-lauf, National Institute for Medical Research, London. The QCPN, 3A10, and 4D9 antibodies were obtained from the Developmental Studies Hybridoma Bank maintained by the Department of Pharmacology and Molecular Sciences, the Johns Hopkins University School of Medicine (Baltimore, MD), and the Department of Biology, University of Iowa (Iowa City, IA), under Contract NO1-HD-2-3144 from the NICHD. This research was supported by NIH Grant NS 18112 to G.C.S.; FIS Grant 94-0431 and DGICYT Grant PR95-243 of the Spanish Government to V.G.M.; grant of the Junta de Extremadura to C.L.S.; and NIH Grants HL53351, AR40339, and AR39849, as well as grants from the Muscular Dystrophy Association and the Human Frontier Science Program, to E.N.O.; D.K.D. was supported by NIH Developmental Biology Training Grant 1T32 HD07491-01.
PY - 1997/1/1
Y1 - 1997/1/1
N2 - We examined the ability of epiblast regions of known prospective fate from the late gastrula/early neurula stage of avian embryos to self-differentiate when placed heterotopically, testing their state of commitment. Three sites were examined: paranodal prospective neural plate ectoderm, containing cells fated to form a portion of the lateral wall of the neural tube at essentially all rostrocaudal levels of the neuraxis; prospective mesoderm from the caudolateral epiblast, containing cells fated to ingress through the primitive streak and to form lateral plate mesoderm; and prospective mesoderm from one level of the primitive streak, containing cells fated to continue ingressing and form paraxial mesoderm. Grafts from all sites exhibited plasticity. Grafts from the prospective neural plate ectoderm could readily substitute for regions of prospective mesoderm, when transplanted to either the epiblast or primitive streak, undergoing an epithelial-mesenchymal transition and, where appropriate, expressing paraxis, a gene expressed in paraxial mesoderm. Similarly, grafts containing prospective mesoderm from the epiblast could readily substitute for regions of the prospective neural plate ectoderm, undergoing convergent-extension movements characteristic of neuroectodermal cells and expressing appropriate genes such as Engrailed-2 and Hoxb-1. Grafts containing prospective mesoderm from the primitive streak could also incorporate into the neural plate and undergo convergence-extension movements of neurulation, although their principal contribution was to mesodermal and endodermal structures. Collectively, our results demonstrate that at the late gastrula/early neurula stage, germ layer-specific properties are not irrevocably fixed for prospective ectodermal and mesodermal regions of the blastoderm. Moreover, the signals responsible for the induction of these two tissue types must still be present and available at these late stages.
AB - We examined the ability of epiblast regions of known prospective fate from the late gastrula/early neurula stage of avian embryos to self-differentiate when placed heterotopically, testing their state of commitment. Three sites were examined: paranodal prospective neural plate ectoderm, containing cells fated to form a portion of the lateral wall of the neural tube at essentially all rostrocaudal levels of the neuraxis; prospective mesoderm from the caudolateral epiblast, containing cells fated to ingress through the primitive streak and to form lateral plate mesoderm; and prospective mesoderm from one level of the primitive streak, containing cells fated to continue ingressing and form paraxial mesoderm. Grafts from all sites exhibited plasticity. Grafts from the prospective neural plate ectoderm could readily substitute for regions of prospective mesoderm, when transplanted to either the epiblast or primitive streak, undergoing an epithelial-mesenchymal transition and, where appropriate, expressing paraxis, a gene expressed in paraxial mesoderm. Similarly, grafts containing prospective mesoderm from the epiblast could readily substitute for regions of the prospective neural plate ectoderm, undergoing convergent-extension movements characteristic of neuroectodermal cells and expressing appropriate genes such as Engrailed-2 and Hoxb-1. Grafts containing prospective mesoderm from the primitive streak could also incorporate into the neural plate and undergo convergence-extension movements of neurulation, although their principal contribution was to mesodermal and endodermal structures. Collectively, our results demonstrate that at the late gastrula/early neurula stage, germ layer-specific properties are not irrevocably fixed for prospective ectodermal and mesodermal regions of the blastoderm. Moreover, the signals responsible for the induction of these two tissue types must still be present and available at these late stages.
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U2 - 10.1006/dbio.1996.8439
DO - 10.1006/dbio.1996.8439
M3 - Article
C2 - 9015268
AN - SCOPUS:0031055693
SN - 0012-1606
VL - 181
SP - 102
EP - 115
JO - Developmental Biology
JF - Developmental Biology
IS - 1
ER -