| |
FIG. 3. Whole-mount in situ hybridization of XANF-2 to Xenopus embryos. (A) A stage 11 embryo with Xanf-2 staining in the dorsal ectoderm (right), but not in the area of the dorsal lip (arrow). (B) Section showing the dorsal region of a stage 11. embryo after hybridization with XANF-2. The demarcation between inner and outer ectodermal layers and involuting mesoderm is shown with dotted lines. The arrow points to the dorsal lip. (C) Embryos are oriented with the dorsal side up and latera] views have anterior to the left, Lateral view of a stage 14 embryo showing an intense hybridization signal in the anterior dorsal region. At this stage it can be seen that both the outer ectoderm and the inner ectoderm express XANF-2. (D Lateral view of a stage 18 embryo showing hybridization signal in the presumptive pituitary gland area. Ar this stage the entire signal is in the inner ectodermal layers. The outer ectodermal layer and the pharyngeal endoderm do not show any hybridization. (E) Lateral view of a stage 24 embryo with expression localized to the inner ectoderm lying between the forebrain and the cement gland. (F) Lateral view of a stage 32 embryo with XAMF-2 (purple) visualizing the pituitary gland cells migrating under the forebrain area and XCG7 green) showing the cement gland. (G) Anterior view of the stage 14 embryo from C. Expression occurs in a roughly uniform pattern, defining a field of cells termed the upper sensory plate. (H) Anterior view of a stage 16 embryo showing localization of XANF-2 signal, with the anterior dorsal region limited by two regions of more intense hybridization. The dorsal (posterior) limit corresponds to the anterior neural plate, while the ventral (anterior) limit is immediately adjacent to the future cement gland (see I). (I) Anterior view of a stage 19 embryo hybridized with XANF-2 and with a cement gland-specific marker XCG7 (Jamrich and Sato, 1989) showing the close proximity, without overlap, of expression for the two genes. At this stage, XCG 7 is expressed in the outer ectoderm while XANF-2 is expressed in the inner ectoderm, Purple, anterior pituitary anlage; green, cement gland. (J) Anterior view of the stage 32 embryo from D hybridized with XANF-2 and XCG7. Purple, anterior pituitary anlage; green, cement gland.
|
