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Figure 4. Paraxis is expressed in the head mesoderm underlying the neural crest territory. A: Dorsal view of a stage 18 embryo stained for paraxis. Arrow, expression in a region anterior to the paraxial mesoderm. Continuous line, anterior limit of paraxial mesoderm; dashed line, section shown in D. B: Dorsal view of a stage 18 embryo stained for Slug (purple) and 12/101 (brown). Continuous line, anterior limit of paraxial mesoderm; dashed line, section shown in E. C: Higher magnification of anterior region of A. D: Section of embryo shown in A. The section was made just anterior to the somite expression. Note a broad band of expression in the head mesoderm (HM) and no expression in the prechordal mesoderm (PM). NC, neural crest; nt, neural tube. E: Section of embryo shown in B. The section was made at the border of somite expression, to include somite labeling as a landmark. s, somite. F: Summary of paraxis expression in the head mesoderm (HM); PM, prechordal mesoderm; NC, neural crest; nt, neural tube. |
