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Fig. 2. Whole-mount in situ hybridization analysis of Xsap-1 expression during early Xenopus embryogenesis. Staged Xenopus embryos were subjected to whole-mount in situ hybridization with Xsap-1 antisense RNA. (A) Transverse section of a blastula embryo (stage NF8) showing expression in the animal cap. (B) Dorsal view of a late gastrula embryo (stage NF12.5). Xsap-1 is expressed weakly in the notoplate (np) and adjacent regions (stars). (C) Dorsal view of a neurula embryo (stage NF20). Signals are detected in two stripes flanking the dorsal midline (dm) and in the lateral regions of the embryo (stars). (D) Central transversal section of a neurula embryo (stage NF20) with dorsal expression of Xsap-1 in cells of the forming neural tube (nt) and in the sensorial layer of the epidermal ectoderm (arrows). (E) Ventral part of the same section as shown in D. Xsap-1 is expressed in the ventral mesoderm (vm). (F) Lateral view of a tadpole embryo (stage NF36) showing signals in different regions of the head, pronephros and in the somites. (G) Anterior parasagittal section of a tadpole embryo (stage NF36) showing expression in all brain areas (fb, mb, hb; anterior is to the left). (H, I) Details from an anterior parasagittal section of a tadpole embryo (stage NF36). Xsap-1 is expressed in the lens (le), the ear vesicle (ev), and in a region posterior to the ear (arrow in I; in both figures dorsal is oriented to the top). In all figures the bar represents 300 μm. Embryo staging was according to Nieuwkoop and Faber (1967). Abbreviations: a, anterior; an, animal pole; ar, archenteron; ba, branchial arches; bc, blastocoel; bp, blastoporus; bv, brain ventricle; cg, cement gland; dm, dorsal midline; e, eye; ee, epithelial and sensorial layer of epidermal ectoderm; ev, ear vesicle; eym, endodermal yolk mass; fb, forebrain; fg, foregut; hb, hindbrain; he, heart; le, lens; mb, midbrain; no, notochord; np, notoplate; nt, neural tube; p, posterior; pe, pigment epithelium; pn, pronephros; sm, somitic mesoderm; so, somites; v, vegetal pole; vm, ventral mesoderm. |
