Distal expression of sprouty (spry) genes during Xenopus laevis limb development and regeneration.
The eukaryotic Sprouty (Spry) proteins are negative regulators of receptor tyrosine kinase signaling pathways, which in turn provide readout for morphogens such as fibroblast growth factors (Fgfs) that are essential for many developmental processes, including limb development. In a transcriptome analysis of early proximo-distal patterning of the Xenopus laevis limb bud, spry1a, 2 and 4 were predicted to be expressed predominantly in the distal third. Expression of all three in the distal limb initially corresponded to the progress zone mesenchyme, adjacent to the fgf8b-positive cryptic apical ectodermal ridge (AER). Spry2 transcripts were also expressed ectodermally, and later localized to the AER. During formation of the autopod, spry1a and spry4 became restricted to the anterior distal mesenchyme. All three spry genes were re-expressed in the mesenchyme cells of the blastema during hindlimb regeneration, with spry2 also overlapping with the region of fgf8b re-expression. However, the anterior bias seen in developing limbs was not recapitulated. We conclude that Spry1a, 2 and 4 have partially overlapping expression in developing and regenerating Xenopus limbs, which correspond with known areas of Fgf signaling. Sprys may therefore be involved in refining of Fgf signal transduction from the AER during development and regeneration.
Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand.
Yi-Hsuan
YH
Wang
Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand. Electronic address: caroline.beck@otago.ac.nz.
Caroline W
CW
Beck
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D019521:Body Patterning; D005121:Extremities / Q000196:embryology* / Q000502:physiology*; D051524:Fibroblast Growth Factor 8 / Q000235:genetics; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics; D010750:Phosphoproteins / Q000235:genetics; D029867:Xenopus Proteins / Q000235:genetics; D014982:Xenopus laevis / Q000196:embryology*
D048868:Adaptor Proteins, Signal Transducing; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; C538825:SPRY2 protein, Xenopus; C000594919:Spry4 protein, Xenopus; D029867:Xenopus Proteins; C528766:spry1 protein, Xenopus; D051524:Fibroblast Growth Factor 8
Limb bud; Regeneration; Sprouty; Xenopus; fgf10; fgf8