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Fig. 7. The spatial pattern of TSP-1 mRNA expression in tailbud stage embryos. Whole mount in situ hybridization was performed on albino Xenopus embryos fixed at 2 hour intervals from stage 24 through stage 34. Pictured embryos are stage 34 and oriented with anterior to the right and dorsal to the top unless otherwise noted. (C) are views of different optical sections of the embryo in (A), (F) are views of the embryo in (B). (C) and (F) are views from the dorsal side (horizontal) and (D, E, G, H) are different focal planes when viewed from the front (transverse). White arrows indicate staining concentrated in the anterior and posterior limits of r2 and white arrowheads point to the notochord. Black arrowheads indicate expression in the anterior region of r1. Large arrows in (C) and (G) point to nonspecific background staining in the brain ventricle and gut respectively. (D) and (G) are optical transverse sections at the level of the anterior region of r1. (E) is an optical transverse section at the level of r2 and (H) at the level of r4. I: Stage 33 tailbud, frontal view with dorsal oriented to the top of the page. Arrowhead indicates central region of facial epidermis that is devoid of TSP-1 staining. J: Side view of a stage 34 tailbud, arrow indicates intense expression in the pre-chordal plate. Note the strong staining in the region of the brain in contact with the pre-chordal plate. Arrowhead indicates facial epidermal staining. K: Stage 34 tailbud with the focal plane at the level of r4. Arrowhead indicates intense expression within the otic vesicle. L: Stage 33 tailbud, side view in trunk region. Arrowhead indicates TSP-1 mRNA expressing cells at the location of a major blood vessel. |
