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N. Holder et al.
A
Neural Tube
Somite
Anterior
Posterior
B
R2
A3
A4
A5
A6
2
3
4
Fig. 2A,B. The role of Eph/ephrin signalling in controlling directed migration
of the neural crest. A Summary drawing of the expression patterns of ephrinsB I and B2 in the somitic tissue in the chick and rat (dark shading). In the
chick the neural crest cells express EphB3 (light shading). Interactions between receptor and ligand cause repulsion of neural crest cell movement leading to migration of crest cells through the rostral half of the somite (based on
Krull et al. 1997; Wang and Anderson 1997). B Migration of neural crest from
the hindbrain region into the branchial arches is also controlled by Eph/ephrin
signalling. In Xenopus, Ephrin-B2 (dark shading) is expressed in rhombomere
2 (R2), R4 and R6 and EphA4 (light shading) is expressed in R3 and R5. Neural crest cells derived from these rhombomeres also express these ligands and
receptors, and interactions between migrating neural crest cells along their migration pathways into the four branchial arches (numbered) ensures that neural
crest cells from the appropriate rhombomere end up in the appropriate arch.
The receptor EphB 1 is also expressed in the crest of R5 along with EphA4
(hatching), and EphBI is expressed exclusively in R6 neural crest (medium
shading; based on Smith et al. 1997)
N. Holder et al.
A
Neural Tube
Somite
Anterior
Posterior
B
R2
A3
A4
A5
A6
2
3
4
Fig. 2A,B. The role of Eph/ephrin signalling in controlling directed migration
of the neural crest. A Summary drawing of the expression patterns of ephrinsB I and B2 in the somitic tissue in the chick and rat (dark shading). In the
chick the neural crest cells express EphB3 (light shading). Interactions between receptor and ligand cause repulsion of neural crest cell movement leading to migration of crest cells through the rostral half of the somite (based on
Krull et al. 1997; Wang and Anderson 1997). B Migration of neural crest from
the hindbrain region into the branchial arches is also controlled by Eph/ephrin
signalling. In Xenopus, Ephrin-B2 (dark shading) is expressed in rhombomere
2 (R2), R4 and R6 and EphA4 (light shading) is expressed in R3 and R5. Neural crest cells derived from these rhombomeres also express these ligands and
receptors, and interactions between migrating neural crest cells along their migration pathways into the four branchial arches (numbered) ensures that neural
crest cells from the appropriate rhombomere end up in the appropriate arch.
The receptor EphB 1 is also expressed in the crest of R5 along with EphA4
(hatching), and EphBI is expressed exclusively in R6 neural crest (medium
shading; based on Smith et al. 1997)