Myotome formation in the epaxial and hypaxial domains of thoraco-lumbar somites was analyzed using fluorescent vital dye labeling of dermomyotome cells and cell-fate assessment by confocal microscopy. Muscle precursor cells for the epaxial and hypaxial myotomes are predominantly located in the dorsomedial and ventrolateral dermomyotome lips, respectively, and expansion of the dermomyotome is greatest along its mediolateral axis coincident with the dorsalward and ventralward growth directions of the epaxial and hypaxial myotomes. Measurements of the dermomyotome at different stages of development shows that myotome growth begins earlier in the epaxial than in the hypaxial domain, but that after an initial lag phase, both progress at the same rate. A combination of dye injection and/or antibody labeling of early and late-expressed muscle contractile proteins confirms the myotome mediolateral growth directions, and shows that the myotome thickness increases in a superficial (near dermis) to deep (near sclerotome) growth direction. These findings also provide a basis for predicting the following gene expression sequence program for the earliest muscle precursor lineages in mouse embryos: Pax-3 (stem cells), myf-5 (myoblast cells) and myoD (myocytes). The movements and mitotic activity of early muscle precursor cells lead to the conclusion that patterning and growth in the myotome specifically, and in the epaxial and hypaxial domains of the body generally, are governed by morphogenetic cell movements.

REFERENCES

Amthor
H.
,
Christ
B.
,
Patel
K.
(
1999
)
A molecular mechanism enabling continuous embryonic muscle growth—a balance between proliferation and differentiation.
Development
126
,
1041
1053
Aoyama
H.
,
Asamoto
K.
(
1988
)
Determination of somite cells: independence of cell differentiation and morphogenesis.
Development
104
,
15
28
Bober
E.
,
Franz
T.
,
Arnold
H. H.
,
Gruss
P.
,
Tremblay
P.
(
1994
)
Pax-3 is required for the development of limb muscles: a possible role for the migration of dermomyotomal muscle progenitor cells.
Development
120
,
603
612
Borman
W. H.
,
Yorde
D. E.
(
1994
)
Analysis of chick somite myogenesis by in situ confocal microscopy of desmin expression.
J. Histochem. Cytochem
42
,
265
272
Brand-Saberi
B.
,
Ebensperger
C.
,
Wilting
J.
,
Balling
R.
,
Christ
B.
(
1993
)
The ventralizing effect of the notochord on somite differentiation in chick embryos.
Anat. Embryol
188
,
239
245
Brill
G.
,
Kahane
N.
,
Carmeli
C.
,
von Schack
D.
,
Barde
Y. A.
,
Kalcheim
C.
(
1995
)
Epithelial-mesenchymal conversion of dermatome progenitors requires neural tube-derived signals: characterization of the role of Neurotrophin-3.
Development
121
,
2583
2594
Buckingham
M.
(
1992
)
Making muscle in mammals.
Trends Genet
8
,
144
148
Chevallier
A.
,
Kieny
M.
,
Mauger
A.
(
1977
)
Limb-somite relationship: origin of the limb musculature.
J. Embryol. Exp. Morphol
41
,
245
258
Christ
B.
,
Brand-Saberi
B.
,
Grim
M.
,
Wilting
J.
(
1992
)
Local signalling in dermomyotomal cell type specification.
Anat. Embryol
186
,
505
510
Christ
B.
,
Jacob
H.
,
Jacob
M.
(
1974
)
Uber den ursprung der flugelmuskulature.
Experientia
30
,
1446
1448
Christ
B.
,
Jacob
H. J.
,
Jacob
M.
(
1977
)
Experimental analysis of the origin of the wing musculature in avian embryos.
Anat. Embryol
150
,
171
186
Christ
B.
,
Jacob
M.
,
Jacob
H. J.
(
1983
)
On the origin and development of the ventrolateral abdominal muscles in the avian embryo.
Anat. Embryol
166
,
87
107
Christ
B.
,
Ordahl
C. P.
(
1995
)
Early stages of chick somite development.
Anat. Embryol. (Berl)
191
,
381
396
Cossu
G.
,
Kelly
R.
,
Tajbakhsh
S.
,
Di Donna
S.
,
Vivarelli
E.
,
Buckingham
M.
(
1996
)
Activation of different myogenic pathways: myf-5 is induced by the neural tube and MyoD by the dorsal ectoderm in mouse paraxial mesoderm.
Development
122
,
429
437
Currie
P.
,
Ingham
P. W.
(
1998
)
The generation and interpretation of positional information within the vertebrate myotome.
Mech. Dev
73
,
3
21
de la Brousse
C. F.
,
Emerson
C. P.
(
1990
)
Localized expression of a myogenic regulatory gene, qmf1, in the somite dermatome of avian embryos.
Genes Dev
4
,
567
581
Denetclaw
W. F.
Jr.
,
Christ
B.
,
Ordahl
C. P.
(
1997
)
Location and growth of epaxial myotome precursor cells.
Development
124
,
1601
1610
Dietrich
S.
,
Schubert
F. R.
,
Healy
C.
,
Sharpe
P. T.
,
Lumsden
A.
(
1998
)
Specification of the hypaxial musculature.
Development
125
,
2235
2249
Dietrich
S.
,
Schubert
F. R.
,
Lumsden
A.
(
1997
)
Control of dorsoventral pattern in the chick paraxial mesoderm.
Development
124
,
3895
3908
Fan
C.-M.
,
Lee
C. S.
,
Tessier-Lavigne
M.
(
1997
)
A role for WNT proteins in induction of dermomyotome.
Dev. Biol
191
,
160
165
Fan
C.-M.
,
Tessier-Lavigne
M.
(
1994
)
Patterning of mammalian somites by surface ectoderm and notochord: evidence for sclerotome induction by a hedgehog homolog.
Cell
79
,
1175
1186
Gilbert
S. F.
,
Opitz
J. M.
,
Raff
R. A.
(
1996
)
Resynthesizing evolutionary and developmental biology.
Dev. Biol
173
,
357
372
Goulding
M.
,
Lumsden
A.
,
Paquette
A. J.
(
1994
)
Regulation of Pax-3 expression in the dermomyotome and its role in muscle development.
Development
120
,
957
971
Hamburger
V.
,
Hamilton
H. L.
(
1951
)
A series of normal stages in the development of the chick embryo.
J. Morphol
88
,
49
92
Huang
R.
,
Zhi
Q.
,
Ordahl
C. P.
,
Christ
B.
(
1997
)
The fate of the first avian somite.
Anat. Embryol
195
,
435
449
Itoh
M.
,
Arai
K.
,
Uehara
K.
(
1994
)
Localization of type IV collagen in the myotome cells during the somite differentiation in the chick embryo.
Dev. Growth Differ
36
,
427
435
Jacob
M.
,
Christ
B.
,
Jacob
H.
(
1979
)
The migration of myogenic cells from the somites into the leg region of avian embryos.
Anat. Embryol
157
,
291
309
Jacob
M.
,
Christ
B.
,
Jacob
H. J.
(
1978
)
On the migration of myogenic stem cells into the prospective wing region of chick embryos.
Anat. Embryol
153
,
179
193
Kaehn
K.
,
Jacob
H. J.
,
Christ
B.
,
Hinrichsen
K.
,
Poelmann
R. E.
(
1988
)
The onset of myotome formation in the chick.
Anat. Embryol
177
,
191
201
Kahane
N.
,
Cinnamon
Y.
,
Kalcheim
C.
(
1998
)
The cellular mechanism by which the dermomyotome contributes to the second wave of myotome development.
Development
125
,
4259
4271
Keller
R. E.
(
1985
)
The cellular basis of amphibian gastrulation.
Dev. Biol
2
,
241
327
Kieny
M.
,
Mauger
A.
,
Chevallier
A.
,
Pautou
M. P.
(
1988
)
Origin and development of avian skeletal musculature.
Reprod. Nutr. Dev
28
,
673
686
Koseki
H.
,
Wallin
J.
,
Wilting
J.
,
Mizutani
Y.
,
Kispert
A.
,
Ebensperger
C.
,
Herrmann
B. G.
,
Christ
B.
,
Balling
R.
(
1993
)
A role for Pax-1 as a mediator of notochordal signals during the dorsoventral specification of vertebrae.
Development
119
,
649
660
Langman
J.
,
Nelson
G. R.
(
1968
)
A radioautographic study of the development of the somite in the chick embryo.
J. Embryol. exp. Morph
19
,
217
226
Lin
Z.
,
Lu
M. H.
,
Schultheiss
T.
,
Choi
J.
,
Holtzer
S.
,
DiLullo
C.
,
Fischman
D. A.
,
Holtzer
H.
(
1994
)
Sequential appearance of muscle-specific proteins in myoblasts as a function of time after cell division: Evidence for a conserved myoblast differentiation program in skeletal muscle.
Cell Motil. Cytoskel
29
,
1
19
Marcelle
C.
,
Stark
M. R.
,
Bronner-Fraser
M.
(
1997
)
Coordinate actions of BMPs, Wnts, Shh and noggin mediate patterning of the dorsal somite.
Development
124
,
3955
3963
Meunsterberg
A. E.
,
Kitajewski
J.
,
Bumcrot
D. A.
,
McMahon
A. P.
,
Lassar
A. B.
(
1995
)
Combinatorial signaling by Sonic hedgehog and Wnt family members induces myogenic bHLH gene expression in the somite.
Genes Dev
9
,
2911
2922
Moore
S. W.
,
Keller
R. E.
,
Koehl
M. A.
(
1995
)
The dorsal involuting marginal zone stiffens anisotropically during its convergent extension in the gastrula of Xenopus laevis.
Development
121
,
3131
3140
Nusslein-Volhard
C.
,
Roth
S.
(
1989
)
Axis determination in insect embryos.
CIBA Found. Symp
144
,
37
55
Ordahl
C. P.
,
Le Douarin
N. M.
(
1992
)
Two myogenic lineages within the developing somite.
Development
114
,
339
353
Ordahl
C. P.
,
Williams
B. A.
(
1998
)
Knowing chops from chuck: roasting myoD redundancy.
BioEssays
20
,
357
362
Ott
M.
,
Bober
E.
,
Lyons
G.
,
Arnold
H.
,
Buckingham
M.
(
1991
)
Early expression of the myogenic regulatory gene, myf-5, in precursor cells of skeletal muscle in the mouse embryo.
Development
111
,
1097
1107
Palmeirim
I.
,
Henrique
D.
,
Ish-Horowicz
D.
,
Pourquie
O.
(
1997
)
Avian hairy gene expression identifies a molecular clock linked to vertebrate segmentation and somitogenesis.
Cell
91
,
639
648
Pownall
M.
,
Emerson
C.
(
1992
)
Sequential activation of myogenic regulatory genes during somite morphogenesis in quail embryos.
Dev. Biol
151
,
67
79
Roth
S.
,
Stein
D.
,
Neusslein-Volhard
C.
(
1989
)
A gradient of nuclear localization of the dorsal protein determines dorsoventral pattern in the Drosophila embryo.
Cell
59
,
1189
1202
Seno
T.
(
1961
)
An experimental study on the formation of the body wall in the chick.
Acta Anat
45
,
60
82
Smith
T. H.
,
Kachinsky
A. M.
,
Miller
J. B.
(
1994
)
Somite subdomains, muscle cell origins, and the four muscle regulatory factor proteins.
J. Cell Biol
127
,
95
105
Spence
M. S.
,
Yip
J.
,
Erickson
C. A.
(
1996
)
The dorsal neural tube organizes the dermamyotome and induces axial myocytes in the avian embryo.
Development
122
,
231
241
Stern
H. M.
,
Brown
A. M.
,
Hauschka
S. D.
(
1995
)
Myogenesis in paraxial mesoderm: preferential induction by dorsal neural tube and by cells expressing Wnt-1.
Development
121
,
3675
3686
Straus
W. L.
Jr.
,
Rawles
M. E.
(
1953
)
An experimental study of the origin of the trunk musculature and ribs in the chick.
Am. J. Anat
92
,
471
509
Tajbakhsh
S.
,
Rocancourt
D.
,
Buckingham
M.
(
1996
)
Muscle progenitor cells failing to respond to positional cues adopt non-myogenic fates in myf-5 null mice.
Nature
384
,
266
270
Tajbakhsh
S.
,
Rocancourt
D.
,
Cossu
G.
,
Buckingham
M.
(
1997
)
Redefining the genetic hierarchies controlling skeletal myogenesis: Pax-3 and Myf-5 act upstream of MyoD.
Cell
89
,
127
138
Teillet
M.
,
Watanabe
Y.
,
Jeffs
P.
,
Duprez
D.
,
Lapointe
F.
,
Le Douarin
N. M.
(
1998
)
Sonic hedgehog is required for survival of both myogenic and chondrogenic somitic lineages.
Development
125
,
2019
2030
Teillet
M. A.
,
Le Douarin
N. M.
(
1983
)
Consequences of neural tube and notochord excision on the development of the peripheral nervous system in the chick embryo.
Dev. Biol
98
,
192
211
Tosney
K. W.
(
1994
)
Abstract.
J. Cell Biochem
188
,
462
–.
Tosney
K. W.
,
Dehnbostel
D. B.
,
Erickson
C. A.
(
1994
)
Neural crest cells prefer the myotome's basal lamina over the sclerotome as a substratum.
Dev. Biol
163
,
389
406
Viallet
J. P.
,
Prin
F.
,
Olivera-Martinez
I.
,
Hirsinger
E.
,
Pourquiae
O.
,
Dhouailly
D.
(
1998
)
Chick Delta-1 gene expression and the formation of the feather primordia.
Mech. Dev
72
,
159
168
Williams
B. A.
,
Ordahl
C. P.
(
1994
)
Pax-3 expression in segmental mesoderm marks early stages in myogenic cell specification.
Development
120
,
785
796
Williams
L. W.
(
1910
)
The somites of the chick.
Am. J. Anat
11
,
55
100
Wolpert
L.
(
1969
)
Positional information and the spatial pattern of cellular differentiation.
J. Theor. Biol
25
,
1
47
Wolpert
L.
(
1996
)
One hundred years of positional information.
Trends Genet
12
,
359
364
This content is only available via PDF.