An amputation resets positional information to a proximal identity in the regenerating zebrafish caudal fin

BMC Developmental Biology, 2012 · DOI: 10.1186/1471-213X-12-24 · Published: August 25, 2012

Regenerative Medicine Genetics Research Methodology & Design

Simple Explanation

The zebrafish caudal fin has the ability to regenerate various tissues and organs like the heart, spinal cord, retina and fins. In this study, we took advantage of the existence of an excellent morphological reference in the zebrafish caudal fin, the bony ray bifurcations, as a model to study positional information upon amputation. The zebrafish caudal fin is composed of several segmented bony rays, mesenchymal tissue, blood vessels and nerve axons. Each bony ray is made of two concave hemirays and, with the exception of the most lateral rays, is bifurcated in a distal position within the fin. In the zebrafish caudal fin, an amputation triggers a regenerative program that occurs in three phases: wound healing, blastema formation and regenerative outgrowth.

Study Duration

10 Months

Participants

20 adult zebrafish

Evidence Level

Not specified

Key Findings

1
Repeated amputations performed at a long distance from the bifurcation do not change its proximal-distal position in the regenerated fin, while consecutive amputations near the bifurcation induce a positional reset and progressively shift its position distally.
2
The bifurcation position is only further distalized when the second amputation is performed at 1 segment below the bifurcation (near the bifurcation).
3
The dynamics of shh expression do not change with different proximal-distal amputation places, being always expressed in two separate groups of cells in the basal layer of the epidermis.

Research Summary

This study investigates positional information during zebrafish caudal fin regeneration by examining bony ray bifurcations after repeated amputations at different locations. The results show that repeated amputations near the bifurcation cause a distal shift in its position, resetting positional information. The study also explores the roles of Shh and Fgf signaling pathways in determining bifurcation position. The findings suggest that Shh expression is not modulated by the amputation place and that Fgf signaling is not involved in determining the bifurcation position. The researchers conclude that the position of the bony ray bifurcation is progressively shifted to a more distal position when repeated amputations are performed near the bifurcation and that this modulation is regulated by the immediate surrounding tissues.

Practical Implications

Understanding Positional Memory

The findings challenge the idea of a simple mechanism for positional information in regenerating zebrafish fins, offering insights into the complex processes governing tissue regeneration.

Role of Local Interactions

The study highlights the importance of local interactions between different cell types and surrounding tissues in regulating bifurcation position during regeneration.

Rethinking Signaling Pathways

The results suggest that Shh and Fgf signaling may not play the roles previously thought in determining bifurcation position, prompting further investigation into other potential signaling pathways.

Study Limitations

1
The study focuses on a single morphological reference point (bony ray bifurcations), which may limit the understanding of overall positional information.
2
The role of retinoic acid (RA) in positional memory remains poorly understood and requires further investigation.
3
The exact signals involved in providing positional information to the regenerating fin/intact fin tissue remain to be uncovered.

Your Feedback

Was this summary helpful?

Back to Regenerative Medicine