| |
Fig. 2. Expression pattern of XTIF2 mRNA at different developmental stages. (A) Lateral view of a stage 9 embryo. Note the XTIF2 expression in the animal region. (B) Vegetal view of a stage 10 embryo; note the dorsal to ventral gradient of XTIF2 expression in the mesoderm and ectoderm. (C) Sagittal section of a stage 10 embryo viewed from the inside. Note the expression of XTIF2 in the prospective notochord and head mesoderm (arrow and arrowhead, respectively). (D) Dorsal view of a late gastrula (stage 12.5), XTIF2 is clearly expressed in the notochord (arrowhead). (E–G) Stage 16 embryos. (E) Lateral view; XTIF2 can be detected weakly in the anterior region of the embryo and in the epidermis. (F) Sagittal section; XTIF2 mRNA can be detected in the prechordal mesoderm (arrowhead). (G) Transverse section showing strong expression of XTIF2 in the notochord (arrowhead) and weak expression in the lateral mesoderm (white arrow) and neuroectoderm (black arrow). (H–J) Stage 20 embryos. (H) Lateral view; XTIF2 expression becomes stronger in the head region (arrowhead). (I) Sagittal section of a stage 20 embryo showing expression in the notochord and prechordal mesoderm (arrowhead and arrow, respectively). (J) Transverse section of a stage 20 embryo. The expression domains of XTIF2 seen at stage 16 are maintained at this stage. Note the strong expression in the notochord (black arrowhead), and the weak expression in the neural tube (white arrowhead) and somites (white arrow). Higher levels of expression are also detected at the boundary between the neural tube and somites (black arrow). (K–L) Hatching embryos (stage 35). (K) XTIF2 expression is stronger in the head with higher levels in the eye lens (arrowheads). XTIF2 mRNA is also detected in the pronephros (white arrow) and in the ventral region of the embryo (black arrow). Inset shows ventral view of this embryo. XTIF2 is expressed in a V-shaped domain (arrow). (L) Section across the eye level of the head showing strong XTIF2 expression in the eye lens (arrowheads). an, animal; vg, vegetal; b, blastopore; d, dorsal; v, ventral; a, anterior; p, posterior. |
