Xenbase Image ID: 40707

Fig. 1. Spatiotemporal distribution of XElk-1 mRNA and protein. (A) Schematic representation of XElk-1 functional domains. See text for details. (B) Temporal expression of XElk-1; transcripts are maternally expressed and are present throughout early development. These data are representative of two independent experiments. Error bars show standard deviations of technical replicates of a single experiment. (C) Spatial distribution of XElk-1 mRNA in transverse sections of an albino embryo at the neurula stage reveal XElk-1 expression in notochord and somitic mesoderm. (D) Comparison of the amino acid sequences of human (h), Xenopus laevis (Xl) and Xenopus tropicalis (Xt) Elk-1 in the vicinity of human serine 383, which is phosphorylated by MAP kinase. (E) Western blot analysis of XElk-1 phosphorylation in response to FGF. Animal caps derived from embryos that had been injected with 400 pg myc-tagged XElk-1 mRNA were treated with 200 ng/ml bFGF for the indicated times and then subjected to western blotting using an antibody specific for phosphorylated XElk-1 (î±-pElk-1) or a pan-Elk-1 antibody (î±-Elk-1). Levels of phosphorylated XElk-1 are high at time zero, perhaps as a response to dissection ([Christen and Slack, 1999] and [Krain and Nordheim, 1999]) but decline by 45 min unless bFGF is present. (Fâ J) Immunocytochemical analysis of phosphorylated XElk-1 protein. (F, G) Sagittal sections of Xenopus embryos at the early gastrula stage. Control embryos incubated in the absence of primary antibody show only non-nuclear staining in cells of the yolky vegetal hemisphere. Use of an antibody directed against phosphorylated XElk-1 protein reveals staining in nuclei of the animal hemisphere and of the ventral and dorsal mesoderm, especially in the vicinity of the dorsal blastopore lip (arrow, G). (Hâ J) Whole mount immunocytochemistry showing the distribution of phosphorylated XElk-1 at gastrula (H), neurula (I) and tailbud (J) stages. pXElk-1 is enriched in the dorsal midline and extends towards the presumptive forebrain as gastrulation proceeds (arrows, H, I). At the early tailbud stage high levels of pXElk-1 are present in the presomitic mesoderm (arrow, J). Image published in: Nentwich O et al. (2009) Copyright © 2009. Image reproduced with permission of the Publisher, Elsevier B. V. Gene Synonyms Species Stage(s) Tissue elk1.S elk-1, Xelk, Xelk-1 X. laevis Throughout neurula stage notochord somite Image source: Published Larger Image Printer Friendly View

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