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Figure 4. Spatiotemporal expression of XFGFRL1/Xndk and XFGF8 at tail bud stages visualized by whole-mount in situ hybridization. The expression of XFGFRL1 is compared with that of XFGF8 as indicated (XFGFRL1 in black; XFGF8 in blue). ldquo cleared, rdquo embryos were treated with benzyl benzoate/benzyl alcohol to become transparent. A,B: Lateral view. Anterior toward the left; dorsal is upward. Arrowheads (right panels; see also C, right panel) indicate the region that probably corresponds to the boundary of prosomeres 2 and 3 in the diencephalon (see text). C-H: Comparison of XFGFRL1 (left or upper panel) and XFGF8 (right or lower panel) expression by horizontal or transverse (F, upper panel) sections of stage 33/34 (C-G) and stage 26 (H) embryos. C: Expression in the midbrain-hindbrain boundary. Middle panels are enlargement of left panel, showing that XFGFRL1 is expressed in the pineal gland. D: Forebrain expression. XFGF8 is also expressed in anterior head mesenchyme (right panel). E: Eye expression in whole embryos (left panels) and in horizontal sections (middle and right panels). Left panels show enlargement of the head region of the embryos in B. The sections correspond to the position shown by a line with e in left panels. White dotted lines show the outline of the eyes (upper left panel) and the ciliary margin and commissural plate (lower middle panel). White arrowheads show XFGF8 expression in the eye and commissural plate (lower left panel). F: Otic vesicle expression. XFGFRL1 (upper panel) is expressed in ventral and XFGF8 (lower panel) is expressed in the anterior part of the otic vesicles. G: Visceral arch expression. Middle and right panels show enlargement of left panels. Both XFGFRL1 and XFGF8 are expressed in the visceral pouches as indicated by arrows. Turquoise staining seen in the expression of XFGFRL1 was due to depletion of nitro blue tetrazolium inside of embryos by strong staining of the ectodermal region. Thus, XFGFRL1 expression (shown in blue and turquoise) is wider than that of XFGF8. H: Somite expression. Staining is localized to nuclear and perinuclear regions as indicated by arrows. XFGFRL1, Xenopus fibroblast growth factor receptor-like 1; XFGF8, Xenopus fibroblast growth factor-8; cm, ciliary margin; cp, commissural plate; ey, eye; fb, forebrain; le, lens epithelium; me, mesenchyme; mhb, midbrain-hindbrain boundary; ov, otic vesicle; pd, pronephric duct; pg, pineal gland; pn, pronephros; so, somite; tz, transitional zone; va, visceral arch; vp, visceral pouch. Scale bar = 100 mu m. |
