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Fig. 5
Chemokine Receptor Expression Correlates with Prim Stalling in extl3/ext2 Mutants
(A-H) cxcr4b time course in 32-50 hpf siblings and extl3/ext2 mutants. cxcr4b is upregulated at 32-34 hpf and increases as the embryo develops.
(I-P) cxcr7b is expressed normally between 32 and 42 hpf in extl3/ext2 mutants, but becomes downregulated at 44 hpf until it is absent by 50 hpf. These expression changes correlate with the expansion of Wnt signaling ( Figure 2) and slowing down and stalling of the prim.
(Q-X) cxcl12a time course shows that despite the upregulation of cxcl12a at 32 hpf, the prim continues to migrate until cxcr7b is downregulated by 44-46 hpf (M-P). cxcl12a upregulation continues as the extl3/ext2 phenotype becomes severe by 50 hpf (W and X).
(Y, Y′, and Z) extl3/ext2 mutants possess more Engrailed (4D9)-positive medial fast muscle fibers along the trunk. In (Z) the SE is indicated.
See also Figure S4.