The differentiation of neural crest cells from progenitors located in the dorsal neural tube appears to involve three sequential steps: the specification of premigratory neural crest cell fate, the delamination of these cells from the neural epithelium and the migration of neural crest cells in the periphery. BMP signaling has been implicated in the specification of neural crest cell fate but the mechanisms that control the emergence of neural crest cells from the neural tube remain poorly understood. To identify molecules that might function at early steps of neural crest differentiation, we performed a PCR-based screen for genes induced by BMPs in chick neural plate cells. We describe the cloning and characterization of one gene obtained from this screen, rhoB, a member of the rho family GTP-binding proteins. rhoB is expressed in the dorsal neural tube and its expression persists transiently in migrating neural crest cells. BMPs induce the neural expression of rhoB but not the more widely expressed rho family member, rhoA. Inhibition of rho activity by C3 exotoxin prevents the delamination of neural crest cells from neural tube explants but has little effect on the initial specification of premigratory neural crest cell fate or on the later migration of neural crest cells. These results suggest that rhoB has a role in the delamination of neural crest cells from the dorsal neural tube.

REFERENCES

REFERENCES
Aktories
K.
,
Hall
A.
(
1989
)
Botulinum ADP-ribosyltransferase C3: a new tool to study low molecular weight GTP-binding proteins.
Trends Pharmacol. Sci
10
,
415
418
Anderson
D. J.
(
1997
)
Cellular and molecular biology of neural crest cell lineage determination.
Trends Genet
13
,
276
280
Basler
K.
,
Edlund
T.
,
Jessell
T. M.
,
Yamada
T.
(
1993
)
Control of cell pattern in the neural tube: regulation of cell differentiation by dorsalin-1, a novel TGF beta family member.
Cell
73
,
687
702
Brewster
R.
,
Lee
J.
,
Ruiz i Altaba
A.
(
1998
)
Gli/Zic factors pattern the neural plate by defining domains of cell differentiation.
Nature
393
,
579
583
Chardin
P.
(
1988
)
The ras superfamily proteins.
Biochimie
70
,
865
868
Delannet
M.
,
Duband
J. L.
(
1992
)
Transforming growth factor-beta control of cell-substratum adhesion during avian neural crest cell emigration in vitro.
Development
116
,
275
287
Dickinson
M. E.
,
Selleck
M. A.
,
McMahon
A. P.
,
Bronner
F. M.
(
1995
)
Dorsalization of the neural tube by the non-neural ectoderm.
Development
121
,
2099
2106
Dillon
S. T.
,
Feig
L. A.
(
1995
)
Purification and assay of recombinant C3 transferase.
Methods Enzymol
256
,
174
184
Duband
J. L.
,
Monier
F.
,
Delannet
M.
,
Newgreen
D.
(
1995
)
Epithelium-mesenchyme transition during neural crest development.
Acta Anat
154
,
63
78
Foerst-Potts
L.
,
Sadler
T. W.
(
1997
)
Disruption of Msx-1 and Msx-2 reveals roles for these genes in craniofacial, eye, and axial development.
Dev. Dyn
209
,
70
84
Hall
A.
(
1998
)
Rho GTPases and the actin cytoskeleton.
Science
279
,
509
514
Hamburger
V.
,
Hamilton
H.
(
1951
)
A series of normal stages in the development of chick embryo.
J. Morphol
88
,
49
92
Hariharan
I. K.
,
Hu
K. Q.
,
Asha
H.
,
Quintanilla
A.
,
Ezzell
R. M.
,
Settleman
J.
(
1995
)
Characterization of rho GTPase family homologues in Drosophila melanogaster: overexpressing Rho1 in retinal cells causes a late developmental defect.
EMBO J
14
,
292
302
Hay
E. D.
(
1995
)
An overview of epithelio-mesenchymal transition.
Acta Anat
154
,
8
20
Hill
C. S.
,
Wynne
J.
,
Treisman
R.
(
1995
)
The Rho family GTPases RhoA, Rac1, and CDC42Hs regulate transcriptional activation by SRF.
Cell
81
,
1159
1170
Hinsch
K. D.
,
Habermann
B.
,
Just
I.
,
Hinsch
E.
,
Pfisterer
S.
,
Schill
W. B.
,
Aktories
K.
(
1993
)
ADP-ribosylation of Rho proteins inhibits sperm motility.
FEBS Lett
334
,
32
36
Ishizaki
T.
,
Naito
M.
,
Fujisawa
K.
,
Maekawa
M.
,
Watanabe
N.
,
Saito
Y.
,
Narumiya
S.
(
1997
)
p160ROCK, a Rho-associated coiled-coil forming protein kinase, works downstream of Rho and induces focal adhesions.
FEBS Lett
404
,
118
124
Jahner
D.
,
Hunter
T.
(
1991
)
The ras-related gene rhoB is an immediate-early gene inducible by v-Fps, epidermal growth factor, and platelet-derived growth factor in rat fibroblasts.
Mol. Cell. Biol
11
,
3682
3690
Jalink
K.
,
van Corven
E. J.
,
Hengeveld
T.
,
Morii
N.
,
Narumiya
S.
,
Moolenaar
W. H.
(
1994
)
Inhibition of lysophosphatidate-and thrombin-induced neurite retraction and neuronal cell rounding by ADP ribosylation of the small GTP-binding protein Rho.
J. Cell Biol
126
,
801
810
Jiang
R.
,
Lan
Y.
,
Norton
C. R.
,
Sundberg
J. P.
,
Gridley
T.
(
1998
)
The Slug gene is not essential for mesoderm or neural crest development in mice.
Dev. Biol
198
,
277
285
Keely
P. J.
,
Westwick
J. K.
,
Whitehead
I. P.
,
Der
C. J.
,
Parise
L. V.
(
1997
)
Cdc42 and Rac1 induce integrin-mediated cell motility and invasiveness through PI(3)K.
Nature
390
,
632
636
Kozma
R.
,
Sarner
S.
,
Ahmed
S.
,
Lim
L.
(
1997
)
Rho family GTPases and neuronal growth cone remodelling: relationship between increased complexity induced by Cdc42Hs, Rac1, and acetylcholine and collapse induced by RhoA and lysophosphatidic acid.
Mol. Cell. Biol
17
,
1201
1211
Leung
T.
,
Chen
X. Q.
,
Manser
E.
,
Lim
L.
(
1996
)
The p160 RhoA-binding kinase ROK alpha is a member of a kinase family and is involved in the reorganization of the cytoskeleton.
Mol. Cell. Biol
16
,
5313
5327
Liang
P.
,
Pardee
A. B.
(
1992
)
Differential display of eukaryotic messenger RNA by means of the polymerase chain reaction.
Science
257
,
967
971
Liang
P.
,
Averboukh
L.
,
Pardee
A. B.
(
1993
)
Distribution and cloning of eukaryotic mRNAs by means of differential display: refinements and optimization.
Nucleic Acids Res
21
,
3269
3275
Liem
K. F.
Jr.
,
Tremml
G.
,
Roelink
H.
,
Jessell
T. M.
(
1995
)
Dorsal differentiation of neural plate cells induced by BMP-mediated signals from epidermal ectoderm.
Cell
82
,
969
979
Liem
K. F.
Jr.
,
Tremml
G.
,
Jessell
T. M.
(
1997
)
A role for the roof plate and its resident TGFbeta-related proteins in neuronal patterning in the dorsal spinal cord.
Cell
91
,
127
138
Loring
J. F.
,
Erickson
C. A.
(
1987
)
Neural crest cell migratory pathways in the trunk of the chick embryo.
Dev. Biol
121
,
220
236
Madaule
P.
,
Axel
R.
(
1985
)
A novel ras-related gene family.
Cell
41
,
31
40
Malosio
M. L.
,
Gilardelli
D.
,
Paris
S.
,
Albertinazzi
C.
,
de Curtis
I.
(
1997
)
Differential expression of distinct members of Rho family GTP-binding proteins during neuronal development: identification of Rac1B, a new neural-specific member of the family.
J. Neurosci
17
,
6717
6728
Moury
J. D.
,
Jacobson
A. G.
(
1989
)
Neural fold formation at newly created boundaries between neural plate and epidermis in the axolotl.
Dev. Biol
133
,
44
57
Nagai
T.
,
Aruga
J.
,
Takada
S.
,
Gunther
T.
,
Sporle
R.
,
Schughart
K.
,
Mikoshiba
K.
(
1997
)
The expression of the mouse Zic1, Zic2, and Zic3 gene suggests an essential role for Zic genes in body pattern formation.
Dev. Biol
182
,
299
313
Nakagawa
S.
,
Takeichi
M.
(
1995
)
Neural crest cell-cell adhesion controlled by sequential and subpopulation-specific expression of novel cadherins.
Development
121
,
1321
1332
Nakagawa
S.
,
Takeichi
M.
(
1998
)
Neural crest emigration from the neural tube depends on regulated cadherin expression.
Development
125
,
2963
2971
Nakata
K.
,
Nagai
T.
,
Aruga
J.
,
Mikoshiba
K.
(
1997
)
Xenopus Zic3, a primary regulator both in neural and neural crest development.
Proc. Natl Acad. Sci. USA
94
,
11980
11985
Nieto
M. A.
,
Sargent
M. G.
,
Wilkinson
D. G.
,
Cooke
J.
(
1994
)
Control of cell behavior during vertebrate development by Slug, a zinc finger gene.
Science
264
,
835
839
Nishiki
T.
,
Narumiya
S.
,
Morii
N.
,
Yamamoto
M.
,
Fujiwara
M.
,
Kamata
Y.
,
Sakaguchi
G.
,
Kozaki
S.
(
1990
)
ADP-ribosylation of the rho/rac proteins induces growth inhibition, neurite outgrowth and acetylcholine esterase in cultured PC-12 cells.
Biochem. Biophys. Res. Commun
167
,
265
272
Nobes
C. D.
,
Hall
A.
(
1995
)
Rho, rac, and cdc42 GTPases regulate the assembly of multimolecular focal complexes associated with actin stress fibers, lamellipodia, and filopodia.
Cell
81
,
53
62
Olson
M. F.
,
Ashworth
A.
,
Hall
A.
(
1995
)
An essential role for Rho, Rac, and Cdc42 GTPases in cell cycle progression through G1.
Science
269
,
1270
1272
Perona
R.
,
Montaner
S.
,
Saniger
L.
,
Sanchez-Perez
I.
,
Bravo
R.
,
Lacal
J. C.
(
1997
)
Activation of the nuclear factor-kappaB by Rho, CDC42, and Rac-1 proteins.
Genes Dev
11
,
463
475
Revel
J. P.
,
Brown
S. S.
(
1976
)
Cell junctions in development, with particular reference to the neural tube.
Cold Spring Harb. Symp. Quant. Biol
40
,
443
455
Ridley
A. J.
,
Hall
A.
(
1992
)
The small GTP-binding protein rho regulates the assembly of focal adhesions and actin stress fibers in response to growth factors.
Cell
70
,
389
399
Ridley
A. J.
,
Comoglio
P. M.
,
Hall
A.
(
1995
)
Regulation of scatter factor/hepatocyte growth factor responses by Ras, Rac, and Rho in MDCK cells.
Mol. Cell. Biol
15
,
1110
1122
Rosenquist
G. C.
(
1981
)
Epiblast origin and early migration of neural crest cells in the chick embryo.
Dev. Biol
87
,
201
211
Sefton
M.
,
S
S. n.
,
Nieto
M. A.
(
1998
)
Conserved and divergent roles for members of the Snail family of transcription factors in the chick and mouse embryo.
Development
125
,
3111
3121
Sekine
A.
,
Fujiwara
M.
,
Narumiya
S.
(
1989
)
Asparagine residue in the rho gene product is the modification site for botulinum ADP-ribosyltransferase.
J. Biol. Chem
264
,
8602
8605
Selleck
M. A.
,
Bronner-Fraser
M.
(
1995
)
Origins of the avian neural crest: the role of neural plate-epidermal interactions.
Development
121
,
525
538
Shimeld
S. M.
,
McKay
I. J.
,
Sharpe
P. T.
(
1996
)
The murine homeobox gene Msx-3 shows highly restricted expression in the developing neural tube.
Mech. Dev
55
,
201
210
Smith
D. E.
,
Franco del Amo
F.
,
Gridley
T.
(
1992
)
Isolation of Sna, a mouse gene homologous to the Drosophila genes snail and escargot: its expression pattern suggests multiple roles during postimplantation development.
Development
116
,
1033
1039
Stasia
M. J.
,
Jouan
A.
,
Bourmeyster
N.
,
Boquet
P.
,
Vignais
P. V.
(
1991
)
ADP-ribosylation of a small size GTP-binding protein in bovineneutrophils by the C3 exoenzyme of Clostridium botulinum andeffect on the cell motility.
Biochem. Biophys. Res. Commun
180
,
615
622
Takaishi
K.
,
Kikuchi
A.
,
Kuroda
S.
,
Kotani
K.
,
Sasaki
T.
,
Takai
Y.
(
1993
)
Involvement of rho p21 and its inhibitory GDP/GTP exchange protein (rho GDI) in cell motility.
Mol. Cell. Biol
13
,
72
79
Takaishi
K.
,
Sasaki
T.
,
Kato
M.
,
Yamochi
W.
,
Kuroda
S.
,
Nakamura
T.
,
Takeichi
M.
,
Takai
Y.
(
1994
)
Involvement of Rho p21 small GTP-binding protein and its regulator in the HGF-induced cell motility.
Oncogene
9
,
273
279
Thery
C.
,
Sharpe
M. J.
,
Batley
S. J.
,
Stern
C. D.
,
Gherardi
E.
(
1995
)
Expression of HGF/SF, HGF1/MSP, and c-met suggests new functions during early chick development.
Dev. Genet
17
,
90
101
Threadgill
R.
,
Bobb
K.
,
Ghosh
A.
(
1997
)
Regulation of dendritic growth and remodeling by Rho, Rac, and Cdc42.
Neuron
19
,
625
634
Tigyi
G.
,
Fischer
D. J.
,
Sebok
A.
,
Yang
C.
,
Dyer
D. L.
,
Miledi
R.
(
1996
)
Lysophosphatidic acid-induced neurite retraction in PC12 cells: control by phosphoinositide-Ca2+ signaling and Rho.
J. Neurochem
66
,
537
548
Tosney
K. W.
(
1978
)
The early migration of neural crest cells in the trunk region of the avian embryo: an electron microscopic study.
Dev. Biol
62
,
317
333
Tucker
G. C.
,
Aoyama
H.
,
Lipinski
M.
,
Tursz
T.
,
Thiery
J. P.
(
1984
)
Identical reactivity of monoclonal antibodies HNK-1 and NC-1: conservation in vertebrates on cells derived from the neural primordium and on some leukocytes.
Cell Differ
14
,
223
230
Van Aelst
L.
,
D'Souza-Schorey
C.
(
1997
)
Rho GTPases and signaling networks.
Genes Dev
11
,
2295
2322
Wang
W.
,
Chen
X.
,
Xu
H.
,
Lufkin
T.
(
1996
)
Msx3: a novel murinehomologue of the Drosophila msh homeobox gene restricted to the dorsal embryonic central nervous system.
Mech. Dev
58
,
203
215
Watanabe
N.
,
Madaule
P.
,
Reid
T.
,
Ishizaki
T.
,
Watanabe
G.
,
Kakizuka
A.
,
Saito
Y.
,
Nakao
K.
,
Jockusch
B. M.
,
Narumiya
S.
(
1997
)
p140mDia, a mammalian homolog of Drosophila diaphanous, is a target protein for Rho small GTPase and is a ligand for profilin.
EMBO J
16
,
3044
3056
Yamada
T.
,
Pfaff
S. L.
,
Edlund
T.
,
Jessell
T. M.
(
1993
)
Control of cell pattern in the neural tube: motor neuron induction by diffusible factors from notochord and floor plate.
Cell
73
,
673
686
Yamamoto
M.
,
Marui
N.
,
Sakai
T.
,
Morii
N.
,
Kozaki
S.
,
Ikai
K.
,
Imamura
S.
,
Narumiya
S.
(
1993
)
ADP-ribosylation of the rhoA gene product by botulinum C3 exoenzyme causes Swiss 3T3 cells to accumulate in the G1 phase of the cell cycle.
Oncogene
8
,
1449
1455
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