Tbx-2, Tbx-3, Tbx-4 and Tbx-5 chick genes have been isolated and, like the mouse homologues, are expressed in the limb regions. Tbx-2 and Tbx-3 are expressed in anterior and posterior domains in wings and legs, as well as throughout the flank. Of particular interest, however, are Tbx-5, which is expressed in wing and flank but not leg, and Tbx-4, which is expressed very strongly in leg but not wing. Grafts of leg tissue to wing and wing tissue to leg give rise to toe-like or wing-like digits in wing and leg respectively. Expression of Tbx-4 is stable when leg tissue is grafted to wing, and Tbx-5 expression is stable when wing tissue is grafted to leg. Induction of either extra wings or legs from the flank by applying FGF-2 in different positions alters the expression of Tbx-4 and Tbx-5 in such a way that suggests that the amount of Tbx-4 that is expressed in the limb determines the type that will form. The ectopic limb always displays a limb-like Tbx-3 expression. Thus Tbx-4 and Tbx-5 are strong candidates for encoding ‘wingness’ and ‘legness’.

Altabef
M.
,
Clarke
J. D. W.
,
Tickle
C.
(
1997
)
Dorsoventral compartments and origin of apical ectodermal ridge in developing chick limb.
Development
124
,
4547
4556
Agulnik
S. I.
,
Garvey
N.
,
Hancock
S.
,
Ruvinsky
I.
,
Chapman
D. L.
,
Agulnik
I.
,
Bollag
R.
,
Papaioannou
V. E.
,
Silver
L. M.
(
1996
)
Evolution of mouse T-box genes by tandem duplication and cluster dispersion.
Genetics
144
,
249
254
Bamshad
M.
,
Lin
R. C.
,
Law
D. J.
,
Watkins
W. S.
,
Krakowiak
P. A.
,
Moore
M. E.
,
Franceschini
P.
,
Lala
R.
,
Holmes
L. B.
,
Gebuhr
T. C.
,
Schinzel
A.
,
Bruneau
B. G.
,
Seidman
J. G.
,
Seidman
C. E.
,
Jorde
L. B.
(
1997
)
Mutations in human TBX3 alter limb, apocrine, and genital development in ulnar-mammary syndrome.
Nature Genet
16
,
311
316
Basson
C. T.
,
Bachinsky
D. R.
,
Lin
R. C.
,
Levi
T.
,
Elkins
J. A.
,
Soults
J.
,
Grayzel
D.
,
Kroumpouzou
E.
,
Traill
T. A.
,
LeBlanc-Straceski
J.
,
Renault
B.
,
Kucherlapati
R.
,
Seidman
J. G.
,
Seidman
C. E.
(
1997
)
Mutations in Human TBX5 cause limb and cardiac malformation in Holt-Oram Syndrome.
Nature Genet
15
,
30
35
Bollag
R. J.
,
Siegfried
Z.
,
Cebra-Thomas
J. A.
,
Garvey
N.
,
Davison
E. M.
,
Silver
L. M.
(
1994
)
An ancient family of embryonically expressed mouse genes sharing a conserved protein motif with the T locus.
Nature Genet
7
,
383
389
Chapman
D. L.
,
Garvey
N.
,
Hancock
S.
,
Alexiou
M.
,
Agulnik
S. I.
,
Gibson-Brown
J. J.
,
Cebra-Thomas
J.
,
Bollag
R. J.
,
Silver
L. M.
,
Papaioannou
V. E.
(
1996
)
Expression of the T-box family genes, Tbx1-Tbx5, during early mouse development.
Developmental Dynamics
206
,
379
390
Cohn
M. J.
,
Izpisúa-Belmonte
J.-C.
,
Abud
H.
,
Heath
J. K.
,
Tickle
C.
(
1995
)
Fibroblast growth factors induce additional limb development from the flank of chick embryos.
Cell
80
,
739
746
Cohn
M. J.
,
Patel
K.
,
Krumlauf
R.
,
Wilkinson
D. G.
,
Clarke
J. D. W.
,
Tickle
C.
(
1997
)
Hox 9 genes and specification of vertebrate limbs.
Nature
387
,
97
101
Gibson-Brown
J. J.
,
Agulnik
S. I.
,
Chapman
D. L.
,
Alexiou
M.
,
Garvey
N.
,
Silver
L. M.
,
Papaioannou
V. E.
(
1996
)
Evidence of a role for T-box genes in the evolution of limb morphogenesis and the specification of forelimb/hindlimb identity.
Mech. Dev
56
,
93
101
Hamburger
V.
,
Hamilton
H. L.
(
1951
)
A series of normal stages in development of the chick embryo.
J. Morphol
88
,
49
92
Izpisúa-Belmonte
J.-C.
,
DeRobertis
E. M.
,
Storey
K. G.
,
Stern
C. D.
(
1993
)
The homeobox gene goosecoid and the origin of organizer cells in the early chick blastoderm.
Cell
74
,
645
659
Jowett
T.
,
Lettice
L.
(
1994
)
Wholemount in situ hybridization ofzebrafish embryos using a mixture of digoxygenin-and fluorescein-labelled probes.
Trends Genet
10
,
73
74
Kieny
M.
(
1964
)
Etude du mechanisme de la regulation dans le developpement du bourgeon de membre de l'embryon de poulet. II. Regulation des deficiences dans les chimeres ‘aile-patte’ et ‘patte-aile’.
J. Embryol. exp. Morph
12
,
357
371
Kispert
A.
,
Ortner
H.
,
Cooke
J.
,
Herrmann
B. G.
(
1995
)
The chick Brachyury gene: Developmental expression pattern and response to axial induction by localised activin.
Dev. Biol
168
,
406
415
Knezevic
V.
,
De Santo
R.
,
Mackem
S.
(
1997
)
Two novel chick T-box genes related to mouse Brachyury are expressed in different non-overlapping mesodermal domains during gastrulation.
Development
124
,
411
419
Krabbenhoft
K. M.
,
Fallon
J. F.
(
1989
)
The formation of leg or wing specific structures by leg bud cells grafted to the wing bud is influenced by proximity to the apical ridge.
Dev. Biol
131
,
373
382
Li
Q. Y.
,
Newbury-Ecob
R.
,
Terrett
J. A.
,
Wilson
D. I.
,
Curtis
A.
,
Yi
C. H.
,
Bullen
P. J.
,
Strachan
T.
,
Robson
S.
,
Bonnet
D.
,
Young
I. E.
,
Raeburn
J. A.
,
Buckler
A. J.
,
Gebuhr
T.
,
Law
D. J.
,
Brook
J. D.
(
1997
)
Holt-Oram syndrome is caused by mutations in TBX5, a member of the Brachyury (T) gene family.
Nature Genet
15
,
21
29
Ohuchi
H.
,
Nakagawa
T.
,
Yamauchi
M.
,
Ohata
Y.
,
Yoshioka
H.
,
Kuwana
T.
,
Mima
T.
,
Nohno
T.
,
Noji
S.
(
1995
)
An additional limb can be induced from the flank of the chick embryo by FGF4.
Biochem. Biophys. Res. Commun
209
,
809
806
Ohuchi
H.
,
Takeuchi
J.
,
Yoshiyasu
H.
,
Ishimaru
Y.
,
Ogura
K.
,
Takahashi
N.
,
Ogura
T.
,
Noji
S.
(
1998
)
Correlation of wing-leg identity in ectopic FGF-induced chimeric limbs with the differential expression of chick Tbx5 and Tbx4.
Development
125
,
51
60
Nelson
C. E.
,
Morgan
B. A.
,
Burke
A. C.
,
Laufer
E.
,
DiMambro
E.
,
Murtaugh
C.
,
Gonzalez
E.
,
Tessarollo
L.
,
Parada
L. F.
,
Tabin
C.
(
1996
)
Analysis of Hox gene expression in the chick limb bud.
Development
122
,
1449
1466
Saunders
J. W.
,
Cairns
J. M.
,
Gasseling
M. T.
(
1957
)
The role of theapical ridge of ectoderm in the differentiation of the morphological structure and inductive specificity of limb parts in the chick.
J. Morphol
101
,
57
88
Saunders
J. W.
,
Gasseling
M. T.
(
1959
)
The differentiation of prospective thigh mesoderm grafted beneath the apical ectodermal ridge of the wing bud in the chick embryo.
Dev. Biol
1
,
281
301
Shang
J.
,
Luo
Y.
,
Clayton
D. A.
(
1997
)
Backfoot is a novel homeobox gene expressed in the mesenchyme of developing hind limb.
Dev. Dynam
209
,
242
253
Wilkinson
D. G.
,
Bhatt
S.
,
Herrmann
B. G.
(
1990
)
Expression pattern of the mouse T gene and its role in mesoderm formation.
Nature
343
,
657
659
Wilkinson
D. G.
,
Nieto
A. M.
(
1993
)
Detection of messenger RNA by in situ hybridisation to tissue sections and wholemounts.
Methods Enzymol
225
,
361
73
Vargesson
N.
,
Clarke
J. D. W.
,
Vincent
K.
,
Coles
C.
,
Wolpert
L.
,
Tickle
C.
(
1997
)
Cell fate in the chick limb bud and relationship to gene expression.
Development
124
,
1909
1918
Zwilling
E.
(
1955
)
Ectoderm-mesoderm relationship in the development of the chick embryo limb bud.
J. Exp. Zool
128
,
423
441
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