A highly conserved TGF-β signaling pathway is involved in the establishment of the dorsoventral axis of the vertebrate embryo. Specifically, Bone Morphogenetic Proteins (Bmps) pattern ventral tissues of the embryo while inhibitors of Bmps, such as Chordin, Noggin and Follistatin, are implicated in dorsal mesodermal and neural development. We investigated the role of Tolloid, a metalloprotease that can cleave Chordin and increase Bmp activity, in patterning the dorsoventral axis of the zebrafish embryo. Injection of tolloid mRNA into six dorsalized mutants rescued only one of these mutants, mini fin. Through chromosomal mapping, linkage and cDNA sequence analysis of several mini fin alleles, we demonstrate that mini fin encodes the tolloid gene. Characterization of the mini fin mutant phenotype reveals that Mini fin/Tolloid activity is required for patterning ventral tissues of the tail: the ventral fin, and the ventroposterior somites and vasculature. Gene expression studies show that mfn mutants exhibit reduced expression of ventrally restricted markers at the end of gastrulation, suggesting that the loss of ventral tail tissues is caused by a dorsalization occurring at the end of gastrulation. Based on the mini fin mutant phenotype and the expression of tolloid, we propose that Mini fin/Tolloid modifes the Bmp activity gradient at the end of gastrulation, when the ventralmost marginal cells of the embryo are in close proximity to the dorsal Chordin-expressing cells. At this time, unimpeded Chordin may diffuse to the most ventral marginal regions and inhibit high Bmp activity levels. In the presence of Mini fin/Tolloid, however, Chordin activity would be negatively modulated through proteolytic cleavage, thereby increasing Bmp signaling activity. This extracellular mechanism is amplified by an autoregulatory loop for bmp gene expression.

Reference

Akimenko
M.-A.
,
Ekker
M.
,
Wegner
J.
,
Lin
W.
,
Westerfield
M.
(
1994
)
Combinatorial expression of three zebrafish genes related to distal-less: Part of a homeobox gene code for the head.
J. Neurosci
14
,
3475
3486
Akimenko
M. A.
,
Johnson
S. L.
,
Westerfield
M.
,
Ekker
M.
(
1995
)
Differential induction of four msx homeobox genes during fin development and regeneration in zebrafish.
Development
121
,
347
357
Arora
K.
,
Nusslein-Volhard
C.
(
1992
)
Altered mitotic domains reveal fate map changes in Drosophila embryos mutant for zygotic dorsoventral patterning genes.
Development
114
,
1003
1024
Biehs
B.
,
François
V.
,
Bier
E.
(
1996
)
The Drosophila short gastrulation gene prevents Dpp from autoactivating and suppressing neurogenesis in the neuroectoderm.
Genes Dev
10
,
2922
2934
Blader
P.
,
Rastegar
S.
,
Fischer
N.
,
Strähle
U.
(
1997
)
Cleavage of the BMP-4 antagonist Chordin by Zebrafish Tolloid.
Science
278
,
1937
1940
Bode
W.
,
Gomis-Ruth
F. X.
,
Huber
R.
,
Zwilling
R.
,
Stöcker
W.
(
1992
)
Structure of astacin and implications for activation of astacins and zinc-ligation of collagenases.
Nature
358
,
164
167
Bork
P.
,
Beckmann
G.
(
1993
)
The CUB Domain A Widespread Module in Developmentally Regulated Proteins.
J. Molec. Biol
231
,
539
545
Catala
M.
,
Teillet
M.-A.
,
Le Douarin
N. M.
(
1995
)
Organization and development of the tail bud analyzed with the quail-chick chimaera system.
Mech. Dev
51
,
51
65
Chevrette
M.
,
Joly
L.
,
Tellis
P.
,
Ekker
M.
(
1997
)
Contribution of zebrafish-mouse cell hybrids to the mapping of the zebrafish genome.
Biochem. Cell Biol
75
,
641
649
Davis
C. G.
(
1990
)
The many faces of epidermal growth factor repeats.
New Biologist
2
,
410
419
De Robertis
E. M.
,
Sasai
Y.
(
1996
)
A common plan for dorsoventral patterning in Bilateria.
Nature
380
,
37
40
Dosch
R.
,
Gawantka
V.
,
Delius
H.
,
Blumenstock
C.
,
Niehrs
C.
(
1997
)
Bmp-4 acts as a morphogen in dorsoventral mesoderm patterning in Xenopus.
Development
124
,
2325
2334
Ekker
M.
,
Speevak
M. D.
,
Martin
C. C.
,
Joly
L.
,
Giroux
G.
,
Chevrette
M.
(
1996
)
Stable transfer of zebrafish chromosome segments into mouse cells.
Genomics
33
,
57
64
Ferguson
E.
,
Anderson
K.
(
1992
)
Decapentaplegic acts as a morphogen to organize dorsal-ventral pattern in the Drosophila embryo.
Cell
71
,
451
461
Ferguson
E. L.
,
Anderson
K. V.
(
1992
)
Localized enhancement and repression of the activity of the TGF-family member, decapentaplegic, is necessary for dorsal-ventral pattern formation in the Drosophila embryo.
Development
114
,
583
597
Fisher
S.
,
Amacher
S. L.
,
Halpern
M. E.
(
1997
)
Loss of cerebum function ventralizes the zebrafish embryo.
Development
124
,
1301
1311
Fouquet
B.
,
Weinstein
B. M.
,
Serluca
F. C.
,
Fishman
M. C.
(
1997
)
Vessel patterning in the embryo of the zebrafish: guidance by notochord.
Dev. Biol
183
,
37
48
Fukagawa
M.
,
Suzuki
N.
,
Hogan
B. L.
,
Jones
M. C.
(
1994
)
Embryonic expression of mouse bone morphogenetic protein-1 (BMP-1), which is related to the Drosophila dorsoventral gene tolloid and encodes a punative astacin metalloendopeptidase.
Dev. Biol
163
,
175
183
Gont
L.
,
Steinbeisser
H.
,
Blumberg
B.
,
De Robertis
E.
(
1993
)
Tail formation as a continuation of gastrulation: the multiple cell populations ofthe Xenopus tailbud derive from the late blastopore lip.
Development
119
,
991
1004
Goodman
S. A.
,
Albano
R.
,
Wardel
F. C.
,
Matthews
G.
,
Tannahill
D.
,
Dale
L.
(
1998
)
BMP1-Related Metalloproteinases Promote the Development of Ventral Mesoderm in Early Xenopus Embryos.
Dev. Biol
195
,
144
157
Graff
J. M.
(
1997
)
Embryonic patterning: To BMP or not to BMP, that is the question.
Cell
89
,
171
174
Hammerschmidt
M.
,
Pelegri
F.
,
Mullins
M. C.
,
Kane
D. A.
,
van Eeden
F. J. M.
,
Granato
M.
,
Brand
M.
,
Furutani-Seiki
M.
,
Haffter
P.
,
Heisenberg
,
Nusslein-Volhard
C.
, et al. 
(
1996
)
dino and mercedes, two genes regulating dorsal development in the zebrafish embryo.
Development
123
,
95
102
Hammerschmidt
M.
,
Serbedzija
G. N.
,
McMahon
A. P.
(
1996
)
Genetic analysis of dorsoventral pattern formation in zebrafish: requirment of a BMP-like ventralizing activity and its dorsal repressor.
Genes Dev
10
,
2452
2461
Hogan
B. L.
(
1996
)
Bone morphogenic proteins: mulitifunctional regulators of vertebrate development.
Genes Dev
10
,
1580
1594
Joly
J. S.
,
Joly
C.
,
Schulte-Merker
S.
,
Boulekbache
H.
,
Condamine
H.
(
1993
)
The ventral and posterior expression of the zebrafish homeobox gene eve1 is perturbed in dorsalized and mutant embryos.
Development
119
,
1261
1275
Jones
C. M.
,
Lyons
K. M.
,
Lapan
P. M.
,
Wright
C. V. E.
,
Hogan
B. L. M.
(
1992
)
DVR-4 (Bone morphogenetic protein-4) as a posterior-ventralizing factor in Xenopus mesoderm induction.
Development
115
,
639
647
Jones
C. M.
,
Smith
J. C.
(
1998
)
Establishment of a BMP-4 morphogen gradient by long-range inhibition.
Dev. Biol
194
,
12
17
Kanki
J. P.
,
Ho
R. K.
(
1997
)
The development of the posterior body in zebrafish.
Development
124
,
881
893
Kim
J.
,
Ault
K. T.
,
Chen
H.-D.
,
Xu
R.-H.
,
Roh
D.-H.
,
Lin
M. C.
,
Park
M.-J.
,
Kung
H.-F.
(
1998
)
Transcriptional regulation of BMP-4 in the Xenopus embryo: analysis of genomic BMP-4 and its promoter.
Biochem. Biophys. Res. Commun
250
,
516
530
Kimmel
C. B.
,
Ballard
W. W.
,
Kimmel
S. R.
,
Ullmann
B.
,
Schilling
T.
(
1995
)
Stages of embryonic development of the zebrafish.
Dev. Dyn
203
,
253
310
Kishimoto
Y.
,
Lee
K. H.
,
Zon
L.
,
Hammerschmidt
M.
,
Schulte-Merker
S.
(
1997
)
The molecular nature of zebrafish swirl: BMP2 function is essential during early dorsoventral patterning.
Development
124
,
4457
4466
Knapik
E. W.
,
Goodman
A.
,
Atkinson
O. S.
,
Roberts
C. T.
,
Shiozawa
M.
,
Sim
C. U.
,
Weksler-Zangen
S.
,
Trolliet
M. R.
,
Futrell
C.
,
Innes
B. A.
, et al. 
(
1996
)
A reference cross for the zebrafish (Danio rerio) anchored with simple sequence length polymorphisms.
Development
123
,
451
460
Knapik
E. W.
,
Goodman
A.
,
Ekker
M.
,
Chevrette
M.
,
Delgado
J.
,
Neuhauss
S.
,
Shimoda
N.
,
Driever
W.
,
Fishman
M. C.
,
Jacob
H. J.
(
1998
)
A microsatellite genetic linkage map for zebrafish (Danio rerio).
Nat. Genet
18
,
338
343
Knecht
A. K.
,
Harland
R. M.
(
1997
)
Mechanisms of dorsal-ventral patterning in noggin-induced neural tissue.
Development
124
,
2477
2488
Knezevic
V.
,
De Santo
R.
,
Mackem
S.
(
1998
)
Continuing organizer function during chick tail development.
Development
125
,
1791
1801
Lee
R.
,
Stainier
D.
,
Weinstein
B.
,
Fishman
M.
(
1994
)
Cardiovascular development in the zebrafish. II. Endocardial progenitors are sequestered within the heart field.
Development
120
,
3361
3366
Liao
W.
,
Bisgrove
B. W.
,
Sawyer
H.
,
Hug
B.
,
Bell
B.
,
Peters
K.
,
Grunwald
D. J.
,
Stainier
D. Y. R.
(
1997
)
The zebrafish gene cloche acts upstream of a flk-1 homologue to regulate endothelial cell differentiation.
Development
124
,
381
389
Lin
J. J.
,
Maeda
R.
,
Ong
R. C.
,
Kim
J.
,
Lee
L. M.
,
Kung
H. F.
,
Maeno
M.
(
1997
)
XBMP-1B (Xtld), a Xenopus homolog of dorso-ventral polarity gene in Drosophila, modifies tissue phenotypes of ventral explants.
Develop. Growth Differ
39
,
43
51
Maeno
M.
,
Xue
Y.
,
Wood
T. I.
,
Ong
R. C.
,
Kung
H.
(
1993
)
Cloning and expression of cDNA encoding Xenopus laevis bone morphogenetic protein-1 during early embryonic development.
Gene
134
,
257
261
Marques
G.
,
Musacchio
M.
,
Shimell
M. J.
,
Wunnenberg-Stapleton
K.
,
Cho
K. W. Y.
,
O'Connor
M. B.
(
1997
)
Production of a DPP Activity Gradient in the Early Drosophila Embryo through the Opposing Actions of the SOG and TLD Proteins.
Cell
91
,
417
426
Metz
A.
,
Knöchel
S.
,
Buchler
P.
,
Köster
M.
,
Knöchel
W.
(
1998
)
Structural and functional analysis of the BMP-4 promoter in early embryos of Xenopus laevis.
Mech. Dev
74
,
29
39
Miller-Bertoglio
V.
,
Fisher
S.
,
Sanchez
A.
,
Mullins
M. C.
,
Halpern
M. E.
(
1997
)
Differential regulation of chordin expression domains in mutant zebrafish.
Dev. Biol
192
,
537
550
Mullins
M. C.
(
1998
)
Holy Tolloido: Tolloid cleaves Sog/Chordin to free DPP/Bmps.
Trends Genet
14
,
127
129
Mullins
M. C.
(
1999
)
Embryonic axis formation in the zebrafish.
In. Methods in Cell Biology
59
,
157
176
Mullins
M. C.
,
Hammerschmidt
M.
,
Kane
D. A.
,
Odenthal
J.
,
Brand
M.
,
van Eeden
F. J. M.
,
Furutani-Seiki
M.
,
Granato
M.
,
Haffter
P.
,
Heisenberg
,
Nusslein-Volhard
C.
, et al. 
(
1996
)
Genes establishing dorsoventral pattern formation in the zebrafish embryo: the ventral specifying genes.
Development
123
,
81
93
Neave
B.
,
Holder
N.
,
Patient
R.
(
1997
)
A graded response to BMP-4 spatially coordinates patterning of the mesoderm and ectoderm in the zebrafish.
Mech. Dev
62
,
183
195
Nguyen
M.
,
Park
S.
,
Marques
G.
,
Arora
K.
(
1998
)
Interpretation of a BMP activity gradient in Drosophila embryos depends on synergistic signaling by two type I receptors, SAX and TkV.
Cell
95
,
495
506
Nguyen
V. H.
,
Schmid
B.
,
Trout
J.
,
Connors
S. A.
,
Ekker
M.
,
Mullins
M. C.
(
1998
)
Ventral and Lateral Regions of the Zebrafish Gastrula, Including the Neural Crest Progenitors, are Established by a bmp2b / swirl Pathway of Genes.
Dev. Biol
199
,
93
110
Nikaido
M.
,
Tada
M.
,
Saji
T.
,
Ueno
N.
(
1997
)
Conservation of BMP signaling in zebrafish mesoderm patterning.
Mech. Dev
61
,
75
88
Pasteels
J.
(
1943
)
Proliferations et croissance dans la gastrulation et la formation dela queue des Vertebres.
Arch. Biol
54
,
1
51
Piccolo
S.
,
Agius
E.
,
Lu
B.
,
Goodman
S.
,
Dale
L.
,
De Robertis
E. M.
(
1997
)
Cleavage of Chordin by Xolloid Metalloprotease Suggests a Role for Proteolytic Processing in the Regulation of Spemann Organizer Activity.
Cell
91
,
407
416
Schulte-Merker
S.
,
Ho
R. K.
,
Herrmann
B. G.
,
Nusslein-Volhard
C.
(
1992
)
The protein product of the zebrafish homologue of the mouse T -gene is expressed in nuclei of the germ ring and the notochord of the early embryo.
Development
116
,
1021
–.
Schulte-Merker
S.
,
Lee
K. J.
,
McMahon
A. P.
,
Hammerschmidt
M.
(
1997
)
The zebrafish organizer requires chordino.
Nature
387
,
862
863
Solnica-Krezel
L.
,
Stemple
D. L.
,
Mountcastle-Shah
E.
,
Rangini
Z.
,
Neuhauss
S. C. F.
,
Malicki
J.
,
Schier
A. F.
,
Stanier
D. Y. R.
,
Zwartkruis
F.
,
Abdelilah
S.
,
Driever
W.
(
1996
)
Mutations affecting cell fates and cellular rearrangements during gastrulation in zebrafish.
Development
123
,
67
80
Stöcker
W.
,
Gomis-Ruth
F. X.
,
Bode
W.
,
Zwilling
R.
(
1993
)
Implications of the three-dimensional structure of astacin for the structure and function of the astacin family of zinc-endopeptidases.
Eur. J. Biochem
214
,
215
231
Suzuki
N.
,
Labosky
P. A.
,
Furuta
Y.
,
Hargett
L.
,
Dunn
R.
,
Fogo
A. B.
,
Takahara
K.
,
Peters
D. M. P.
,
Greenspan
D. S.
,
Hogan
B. L. M.
(
1996
)
Failure of ventral body wall closure in mouse embryos lacking procollagen C-proteinase encoded by BMP1, a mammalian gene related in Drosophila tolloid.
Development
122
,
3587
3595
Takahara
K.
,
Brevard
R.
,
Hoffman
G. G.
,
Suzuki
N.
,
Greenspan
D. S.
(
1996
)
Characterization of a novel gene product (mammalian Tolloid-like) with high similarity to mammalian Tolloid/Bone Morphogenic Protein-1.
Genomics
34
,
157
165
Takahara
K.
,
Lyons
G. E.
,
Greenspan
D. S.
(
1994
)
Bone Morphogenic Protein-1 and a Mammalian Tolloid Homologue (mTld) Are Encoded by Alternatively Spliced Transcripts Which Are Differentially Expressed in Some Tissues.
J. Biol. Chem
269
,
32572
32578
Thompson
M. A.
,
Ransom
D. G.
,
Pratt
S. J.
,
MacLennan
H.
,
Kieran
M. W.
,
Detrich
H. W.
,
Vail
B.
,
Huber
T. L.
,
Paw
B.
,
Brownlie
A. J.
,
Zon
L. I.
, et al. 
(
1998
)
The cloche and spadetail genes differentially affect hematopoiesis and vasculogenesis.
Dev. Biol
197
,
248
269
Thomsen
G. H.
(
1997
)
Antagonism within and around the organizer: BMP inhibitors in vertebrate body patterning.
Trends Genet
13
,
209
211
Tucker
A. S.
,
Slack
J. M. W.
(
1995
)
The Xenopus laevis tail-forming region.
Development
121
,
249
262
Weinberg
E. S.
,
Allende
M. L.
,
Kelly
C. L.
,
Abdelhamid
A.
,
Murakami
T.
,
Andermann
P.
,
Doerre
G.
,
Grunwald
D. J.
,
Riggleman
B.
(
1996
)
Developmental regulation of zebrafish MyoD in wild-type, no tail, and spadetail embryos.
Development
122
,
271
280
Wilson
P. A.
,
Lagna
G.
,
Suzuki
A.
,
Hemmati-Brivanlou
A.
(
1997
)
Concentration-dependent patterning of the Xenopus ectoderm by BMP4 and its signal transducer Smad1.
Development
124
,
3177
3184
Woo
K.
,
Fraser
S. E.
(
1998
)
Specification of the Hindbrain Fate in the Zebrafish.
Dev. Biol
197
,
283
296
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