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Fig. 1. Expression and protein sequence of XGadd45-γ. (A) Vegetal view; (B–F,I) dorsal views; (G) ventral view; (H,J,K) lateral views. (A) XGadd45-γ is expressed in the dorsal mesoderm (arrowhead) at early gastrula stages (stg). Throughout gastrulation, XGadd45-γ is also expressed in scattered cells of the animal region (not shown). (B) At mid-late gastrula, three rows of cells at each side of the midline start to accumulate XGadd45-γ mRNA (arrowheads). (C) These rows of XGadd45-γ expressing cells are clearly visible in the early neurula (black arrowheads). XGadd45-γ is also expressed in forming somites (arrows) (Jen et al., 1999) and in a horseshoe-shaped domain within the anterior neural plate (white arrowhead). This pattern is similar to that of XDl1 (inset). (D) A similar expression profile is observed at mid neurula stages. (D, inset) Transverse section of a mid neurula revealing XGadd45-γ expression in three neuroectodermal rows of cells (black arrowheads), in the notocord (white arrowhead) and in somites (arrow). (E) Mid neurula doubly hybridized for XGadd45-γ and N-tubulin and shown after the first chromogenic reaction to detect XGadd45-γ mRNA (cian). (F) After second chromogenic reaction to detect N-tubulin (purple). Insets in (E) and (F): high magnifications views of the lateral neural stripe pointed at with an arrowhead in their corresponding panels. During neurula stages, XGadd45-γ is also expressed in the prospective cement gland (G, arrowhead), trigeminal placode (H, arrowhead) and in scattered cells in the non-neural ectoderm (H, arrow). XGadd45-γ expression is detected in the same sites at later stages (I). In late neurula (J) and tailbud stages (K), XGadd45-γ is expressed in territories in which secondary neurogenesis takes place, such as the eye (arrows) and brain (arrowheads). (L–M) Hindbrain transverse sections of tailbud embryos showing XGadd45-γ (L) and XDl1 (M) domains of expression (arrowheads). (N) Amino acid sequence alignment of Xenopus and human Gadd45-γ proteins (accession numbers AJ414384 and AF078078, respectively). Identical residues are indicated by dashes. |
