The human ARF tumor suppressor senses blastema activity and suppresses epimorphic tissue regeneration.

Nadav Ahituv,Jason H Pomerantz,Gayle K Kouklis,Robert G Hesse

doi:10.7554/elife.07702

Abstract

The control of proliferation and differentiation by tumor suppressor genes suggests that evolution of divergent tumor suppressor repertoires could influence species' regenerative capacity. To directly test that premise, we humanized the zebrafish p53 pathway by introducing regulatory and coding sequences of the human tumor suppressor ARF into the zebrafish genome. ARF was dormant during development, in uninjured adult fins, and during wound healing, but was highly expressed in the blastema during epimorphic fin regeneration after amputation. Regenerative, but not developmental signals resulted in binding of zebrafish E2f to the human ARF promoter and activated conserved ARF-dependent Tp53 functions. The context-dependent activation of ARF did not affect growth and development but inhibited regeneration, an unexpected distinct tumor suppressor response to regenerative versus developmental environments. The antagonistic pleiotropic characteristics of ARF as both tumor and regeneration suppressor imply that inducing epimorphic regeneration clinically would require modulation of ARF -p53 axis activation.

Highlights

Urodele amphibians and teleost fish are unique among vertebrates in that they possess the ability to regenerate injured complex structures such as limbs, fins, jaws, and heart by epimorphic regeneration (Morgan, 1901; Brockes and Kumar, 2008; Poss, 2010)
Experiments were performed with ZF4 and zebrafish kidney stromal (ZKS) (Stachura et al, 2009) cells with HeLa cells used as a positive control since they express high levels
We found that the core mammalian tumor suppressor ARF senses regeneration signals and responds to negatively alter the proliferative balance in the zebrafish blastema, greatly perturbing regeneration

Summary

Introduction

Urodele amphibians and teleost fish are unique among vertebrates in that they possess the ability to regenerate injured complex structures such as limbs, fins, jaws, and heart by epimorphic regeneration (Morgan, 1901; Brockes and Kumar, 2008; Poss, 2010). Zebrafish fin regeneration proceeds through steps that include wound healing, blastema formation, and regenerative outgrowth to faithfully restore preinjury structures and size of the fin (Poss et al, 2003). In such highly regenerative species, the blastema consists of a heterogeneous pool of highly proliferative mesenchymal cells that gives rise to the large amount of new tissue in the regenerate (Knopf et al, 2011; Tu and Johnson, 2011). Tumor suppressor genes control the proliferative and differentiated state of cells, and many are developmental regulators critical for normal formation of tissues

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Conclusion