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Published on: February 2, 2016
Distal expression of sprouty (spry) genes during Xenopus laevis limb development and regeneration
Yi-Hsuan Wang1, Caroline W Beck1
1Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand.
Abstract:
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.
Insights
Sprouty (Spry) proteins regulate fibroblast growth factor (FGF) signaling during Xenopus limb development and regeneration. Spry1a, Spry2, and Spry4 show overlapping expression patterns, suggesting a role in refining FGF signal transduction.
Area of Science:
- Developmental Biology
- Regenerative Medicine
- Molecular Signaling
Background:
- Sprouty (Spry) proteins act as negative regulators of receptor tyrosine kinase (RTK) signaling pathways.
- Fibroblast growth factors (Fgfs) are crucial morphogens for developmental processes, including limb formation.
- Spry proteins modulate RTK signaling, influencing developmental patterning.
Purpose of the Study:
- To investigate the expression patterns of Spry1a, Spry2, and Spry4 during Xenopus limb development and regeneration.
- To understand the role of Spry proteins in relation to Fibroblast Growth Factor (FGF) signaling in limb patterning.
- To determine if Spry expression correlates with Fgf signaling during limb development and regeneration.
Main Methods:
- Transcriptome analysis of early Xenopus laevis limb bud patterning.
- Whole-mount in situ hybridization to detect spry gene expression.
- Analysis of spry gene expression during limb development and hindlimb regeneration.
Main Results:
- Spry1a, Spry2, and Spry4 were predominantly expressed in the distal limb bud, correlating with the progress zone mesenchyme and apical ectodermal ridge (AER).
- Spry2 transcripts were also detected in the ectoderm and later in the AER.
- During autopod formation, spry1a and spry4 localized to the anterior distal mesenchyme; all three spry genes were re-expressed in the regenerating blastema, with spry2 overlapping fgf8b expression.
Conclusions:
- Spry1a, Spry2, and Spry4 exhibit partially overlapping expression in developing and regenerating Xenopus limbs.
- Spry expression patterns correspond to known areas of Fgf signaling in the limb.
- Spry proteins likely play a role in refining Fgf signal transduction from the AER during both limb development and regeneration.
