July 1, 2000;
Gdf16, a novel member of the growth/differentiation factor subgroup of the TGF-beta superfamily, is expressed in the hindbrain and epibranchial placodes.
We have isolated and characterized the developmental expression of Xenopus gdf16
, a novel member of the growth/differentiation factor (gdf) gene family. The gdf16
gene encodes a pre-proprotein of 413 amino acids and a mature peptide of 122 amino acids. Gdf16
is most closely related to the zebrafish genes dynamo and radar, but exhibits a completely different expression pattern. Gene expression is detected at early tailbud
(stage 25) in the first two epibranchial placodes and in a hindbrain
-specific domain. As development proceeds, the gene is expressed in all the epibranchial placodes, the hindbrain
, and the diencephalon
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Fig. 2. Analysis of gdf16 expression in Xenopus. (A) Early tailbud stage (25) showing expression of gdf16 in the developing epibranchial facial and glossopharyngeal placodes (closed arrowhead) and neural expression (open arrowhead). (B) Stage 31/32 embryo showing the first vagal epibranchial placode immediately posterior to the first two placodes and the neural expression (open arrowhead). (C) Lateral view and (D) dorsal view of a stage 35 embryo exhibiting expression in the second and third vagal epibranchial placodes (closed arrowhead) posterior to the previous three epibranchial placodes, diencephalon expression (black arrow), and hindbrain (open arrowhead). (E) Transverse section through a stage 35 embryo showing roofplate staining in the diencephalon (black arrow) photographed at 200×. (F) Transverse section through a stage 35 embryo showing neural tube roof plate staining in the hindbrain (open arrowhead) and the glossopharyngeal placodes (closed arrowheads) photographed at 100× magnification. (G) Magnification (400×) of a stage 35 embryo showing the subdermal location of the expression in the glossopharyngeal placode (closed arrowhead). (H) Transverse section through a stage 35 embryo at the anterior border of the hindbrain expression (400×) showing expression in the roofplate of the neural tube. e, eye; hb, hindbrain; mg, midgut; nt, notochord; ov, otic vesicle.