Induction of Apoptosis and CPP32 Expression by Thyroid Hormone in a Myoblastic Cell Line Derived from Tadpole Tail

doi:10.1074/jbc.272.8.5122

Induction of Apoptosis and CPP32 Expression by Thyroid Hormone in a Myoblastic Cell Line Derived from Tadpole Tail*

Yoshio Yaoita^‡ and
Keisuke Nakajima

From the Department of Molecular Neurobiology, Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashidai, Fuchu, Tokyo 183, Japan

^‡ To whom correspondence should be addressed. Tel.: 81-423-25-3881; Fax: 81-423-21-8678.

Abstract

During amphibian metamorphosis, the tail and gills that are useful in aquatic life but inappropriate for terrestrial activity are induced to degenerate completely in several days by endogenous thyroid hormone (TH). The dramatic resorption of the tadpole tail has attracted a good deal of attention as an experimental system of cell death, but the mechanism has not been well characterized. To facilitate in vitro analysis, we have established a myoblast cell line (XLT-15) derived from the Xenopus laevis tadpole tail. This cultured cell line died in response to TH and exhibited positive TUNEL reaction and internucleosomal DNA cleavage. Simultaneously, expression of the Xenopus CPP32/apopain/Yama gene was up-regulated by TH in the cell line as it is in regressing tadpole tail, whereas interleukin-1β-converting enzyme (ICE) mRNA is around 1 copy/cell in tail and undetectable in XLT-15 cells. A CPP32/apopain/Yama inhibitor (acetyl-Asp-Glu-Val-Asp-aldehyde) prevented TH-induced apoptosis of XLT-15 cells, but an ICE inhibitor (acetyl-Tyr-Val-Ala-Asp-aldehyde) did not. These results suggested that an increase of CPP32/apopain/Yama gene expression is involved in TH-dependent apoptosis of XLT-15 and tadpole tail resorption during metamorphosis.

Footnotes

↵* This work was supported in part by a grant-in-aid from the Ministry of Education, Science, and Culture of Japan (to Y. Y.) and a grant from the Uehara Memorial Foundation (to Y. Y.). The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The nucleotide sequences reported in this paper (X-ICE and X-CPP32) have been submitted to the GenBank™/EMBL/DDBJ Data Bank with accession numbers D89784[GenBank] and D89785[GenBank], respectively.
↵¹ The abbreviations used are:

TH

thyroid hormone

ICE

interleukin-1β converting enzyme

PARP

poly(ADP-ribose) polymerase

PCR

polymerase chain reaction

T₃

3,3′,5-triiodo-L-thyronine

Ac-DEVD-CHO

acetyl-L-Asp-Glu-Val-Asp-aldehyde

Ac-YVAD-CHO

acetyl-L-Tyr-Val-Ala-Asp-aldehyde

FCS

fetal calf serum

TUNEL

terminal deoxynucleotidyltransferase-mediated dUTP-X nick end labeling.
↵² Y. Yaoita, unpublished data.
- Received June 17, 1996.
- Revision received October 3, 1996.