1 October 2017 An Inhibitor of Thyroid Hormone Synthesis Protects Tail Skin Grafts Transplanted to Syngenic Adult Frogs
Yuya Nakai, Keisuke Nakajima, Yoshio Yaoita
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Tail regression in amphibian tadpoles during metamorphosis is one of the most dynamic morphological changes in animal development and is induced by thyroid hormone (TH). It has been proposed that tail resorption is driven by immunological rejection in Xenopus laevis, based on experimental evidence showing that larval skin grafts become atrophic on syngenic recipient adult frogs. This led to the hypothesis that tail regression is induced by an immunological rejection against larval skin-specific antigens called Ouro proteins. However, our group has demonstrated that ouro-knockout tadpoles undergo normal metamorphosis, including tail resorption in Xenopus tropicalis, which indicates that the expression of ouro genes is not necessary for tail regression. In the present study, we showed that an inhibitor of TH synthesis promotes the survival of larval tail skin grafts on syngenic adult Xenopus tropicalis frogs. The levels of endogenous THs in adult frogs were also comparable to those in metamorphosing tadpoles of Xenopus laevis with a regressing tail, and TH induced the regression of tadpole tail tips of Xenopus tropicalis in organ culture. Taken together, these results strongly suggest that endogenous THs in the recipient adult frog induce the degeneration of syngenic tail skin grafts.

© 2017 Zoological Society of Japan
Yuya Nakai, Keisuke Nakajima, and Yoshio Yaoita "An Inhibitor of Thyroid Hormone Synthesis Protects Tail Skin Grafts Transplanted to Syngenic Adult Frogs," Zoological Science 34(5), 414-418, (1 October 2017). https://doi.org/10.2108/zs170011
Received: 23 January 2017; Accepted: 1 May 2017; Published: 1 October 2017
anuran metamorphosis
immunological rejection
skin transplantation
tail regression
thyroid hormone
Xenopus tropicalis
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