Grafting experiments previously have established that the notochord affects dorsoventral polarity of the neural tube by inducing the formation of ventral structures such as motor neurons and the floor plate. Here, we examine if the notochord inhibits formation of dorsal structures by grafting a notochord within or adjacent to the dorsal neural tube prior to or shortly after tube closure. In all cases, neural crest cells emigrated from the neural tube adjacent to the ectopic notochord. When analyzed at stages after ganglion formation, the dorsal root ganglia appeared reduced in size and shifted in position in embryos receiving grafts. Another dorsal cell type, commissural neurons, identified by CRABP and neurofilament immunoreactivity, differentiated in the vicinity of the ectopic notochord. Numerous neuronal cell bodies and axonal processes were observed within the induced, but not endogenous, floor plate 1 to 2 days after implantation but appeared to be cleared with time. These results suggest that dorsally implanted notochords cannot prevent the formation of neural crest cells or commissural neurons, but can alter the size and position of neural crest-derived dorsal root ganglia.

REFERENCES

Bronner-Fraser
M.
(
1986
)
Analysis of the early stages of trunk neural crest migration in avian embryos using the monoclonal antibody HNK-1.
Dev. Biol
115
,
44
55
Bronner-Fraser
M.
,
Fraser
S.
(
1988
)
Cell lineage analysis shows multipotentiality of some avian neural crest cells.
Nature
335
,
161
164
Bronner-Fraser
M.
,
Fraser
S.
(
1989
)
Developmental potential of avian trunk neural crest cells in situ.
Neuron
3
,
755
766
Eriksson
U.
,
Hansson
E.
,
Norlinder
H.
,
Busch
C.
,
Sundelin
J.
,
Peterson
P. A.
(
1987
)
Quantitation and tissue localisation of the cellular retinoic acid-binding protein.
J. Cell Physiol
133
,
482
490
Hamburger
V.
,
Hamilton
H. L.
(
1951
)
A series of normal stages in the development of the chick embryo.
J. Morph
88
,
49
92
Lallier
T.
,
Bronner-Fraser
M.
(
1988
)
A spatial and temporal analysis of dorsal root ganglion formation in the avian embryo.
Dev. Biol
127
,
99
112
LeDouarin
N.
(
1974
)
Cell recognition based on natural morphological nuclear markers.
Med. Biol
52
,
281
319
Lee
V.
,
Carden
M.
,
Schlaepfer
W.
,
Trojanowski
J.
(
1987
)
Monoclonal antibodies distinguish several differentially phosphorylated states of the two largest rat neurofilament subunits (NF-H and NF-M) and demonstrate their existence in the normal nervous system of adult rats.
J. Neurosci
7
,
3474
3489
Maden
M.
,
Ong
D. E.
,
Summerbell
D.
,
Chytil
F.
,
Hirst
E. A.
(
1989
)
Cellular retinoic acid binding protein and the role of retinoic acid in the development of the chick embryo.
Dev. Biol
135
,
124
132
Markham
J. A.
,
Vaughn
J. E.
(
1991
)
Migration patterns of sympathetic preganglionic neurons in embryonic rat spinal cord.
J. Neurobiol
22
,
811
822
Moury
J. D.
,
Jacobson
A. G.
(
1990
)
The origins of neural crest cells in the axolotl.
Dev. Biol
141
,
243
253
Newgreen
D.
,
Scheel
M.
,
Kastner
V.
(
1986
)
Morphogenesis of sclerotome and neural crest in avian embryos: In vivo studies on the role of notochordal extracellular matrix.
Cell Tissue Res
244
,
299
313
Pettway
Z.
,
Guillory
G.
,
Bronner-Fraser
M.
(
1990
)
Absence of neural crest cells from the region surrounding the implanted notochords in situ.
Dev. Biol
142
,
335
345
Placzek
M.
,
Tessier-Lavigne
M.
,
Jessell
T.
,
Dodd
J.
(
1990
)
Orientation of commissural axons in vitro in response to a floor plate derived chemoattractant.
Dev. Biol
110
,
19
30
Rickmann
M.
,
Fawcett
J. W.
,
Keynes
R. J.
(
1985
)
The migration of neural crest cells and the growth of motor axons through the rostral half of the chick somite.
J. Embryol.Exp. Morph
90
,
437
455
Sechrist
J.
,
Bronner-Fraser
M.
(
1991
)
Reticular neurons in the chick hindbrain are born prior to neurulation.
Neuron
7
,
947
963
Smith
J.
,
Schoenwolf
G. C.
(
1989
)
Notochordal induction of cell wedging in the chick neural plate and its role in neural tube formation.
J. Exp. Zool
25
,
49
62
Stern
C. D.
,
Artinger
K. B.
,
Bronner-Fraser
M.
(
1991
)
Tissue interactions affecting the migration and differentiation of neural crest cells in the chick embryo.
Development
113
,
207
216
Serbedzija
G.
,
Bronner-Fraser
M.
,
Fraser
S.
(
1989
)
Vital dye analysis of the timing and pathways of avian trunk neural crest cell migration.
Development
106
,
806
816
Serbedzija
G.
,
Fraser
S. E.
,
Bronner-Fraser
M.
(
1990
)
Pathways of trunk neural crest cell migration in the mouse embryo revealed by vital dye analysis.
Development
108
,
605
612
Tessier-Lavigne
M.
,
Placzek
M.
,
Lumsden
A.
,
Dodd
J.
,
Jessell
T. M.
(
1988
)
Chemotropic guidance of developing axons in the mammalian central nervous system.
Nature
336
,
775
778
Tosney
K.W.
,
Oakley
R.A.
(
1990
)
The perinotochordal mesenchyme acts as a barrier to axon advance in the chick embryo: Implications for a general mechanism of axon guidance.
Exp. Neurol
109
,
75
89
van Straaten
H. W. M.
,
Hekking
E. J. L. M.
,
Wiertz-Hoessels
Hoessels F.
,
Drukker
J.
(
1988
)
Effects of the notochord on the differentiation of a floor plate area in the neural tube of the chick embryo.
Anat. Embryol
177
,
317
324
van Straaten
H. W. M.
,
Hekking
J. W. M.
,
Beursgens
J. P. W. M.
,
Terwindt-Rouwenhorst
E.
,
Drukker
J.
(
1989
)
Effect of the notochord on proliferation and differentiation in the neural tube of the chick embryo.
Development
107
,
793
803
Yaginuma
H.
,
Shjiga
T.
,
Homma
S.
,
Ishihara
R.
,
Oppenheim
R.
(
1990
)
Identification of early developing axon projections from spinal interneurons in the chick embryo with a neuron specific-tubulin antibody: evidence for a new ‘pioneer’ pathway in the spinal cord.
Development
108
,
705
716
Yamada
T.
,
Placzek
M.
,
Tanaka
H.
,
Dodd
J.
,
Jessell
T. M.
(
1991
)
Control of cell pattern in the developing nervous system: Polarizing activity of the floor plate and notochord.
Cell
64
,
635
647
This content is only available via PDF.