||FIG. 3. In situ hybridization of Xenopus LTBP-1. (A–J) In situ hybridization. (A): Stage 10.5 (gastrula). Expression of xLTBP-1 is detected
within the organizer region. (B) A section (depicted by the line “i” in A) shows expression is restricted to the dorsal mesoderm of the
organizer (*). (C) Stage 20. Expression of xLTBP-1 in the spinal cord. No expression is seen in the anterior neural plate at this stage.
Anterior/ventral is to the right. (D) Stage 25. Transcripts can be detected throughout the spinal cord region but still not in anterior domains.
(E) A section through the embryo at the level of the spinal cord (indicated by the line “ii” in D); xLTBP-1 RNA expression is seen throughout
the neural tube but not in the notochord at this stage. (F) Expression is also detected in the lateral plate mesoderm, Stage 28. Expression
is seen in the tail, throughout the spinal cord and in the hindbrain. (G) Transverse section through the spinal cord (“iii” in F); xLTBP-1 RNA
is expressed in the mesoderm lateral to the neural tube, in the notochord and in both the roof (white arrow) and floor plates (black arrow).
(H) Midsagital section through the head (line “iv” in F). xLTBP-1 RNA is also expressed in anterior regions, in the hindbrain, and in the
ventral forebrain. Note the expression within the notochord. (I) Stage 35. xLTBP-1 RNA is highly expressed in the muscle blocks
surrounding the spinal cord. It is also expressed in the rhombomeres of the hindbrain, the eye, and the cement gland. High expression is
present in the tailbud cordoneural hinge. (J) Stage 42. Additional xLTBP-1 RNA expression is observed in more anterior regions, including
the heart (white arrow), the branchial arches, and around the eye. anp, anterior neural plate; cg, cement gland; ey, eye; fb, forebrain; hb,
hindbrain; he, heart; nc, notochord. Locations of the sections are indicated by dashed lines. (K) xLTBP-1 RNA expression in dissected
gastrula embryos: Dorsal and ventral marginal zones and animal cap explants were dissected from stage 11 gastrula embryos and analyzed
by RT-PCR. xLTBP-1 was amplified by using the same primers as in Fig. 2 but for 30 cycles. The following controls are included as markers
for the dissected fragments: Chordin (chd) for dorsal mesoderm, Wnt8 for ventral mesoderm, Otx for animal cap, Brachyury (xBra) as a pan
mesodermal marker, and ODC as the loading control.