کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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5901536 | 1156110 | 2012 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: The RNA-binding protein xCIRP2 is involved in apoptotic tail regression during metamorphosis in Xenopus laevis tadpoles The RNA-binding protein xCIRP2 is involved in apoptotic tail regression during metamorphosis in Xenopus laevis tadpoles](/preview/png/5901536.png)
Frog metamorphosis induced by thyroid hormone (TH) involves not only cell proliferation and differentiation in reconstituted organs such as limbs, but also apoptotic cell death in degenerated organs such as tails. However, the molecular mechanisms directing the TH-dependent cell fate determination remain unclear. We have previously identified from newts an RNA-binding protein (nRBP) acting as the regulator governing survival and death in germ cells during spermatogenesis. To investigate the molecular events leading the tail resorption during metamorphosis, we analyzed the expression, the functional role in apoptosis, and the regulation of xCIRP2, a frog homolog of nRBP, in tails of Xenopus laevis tadpoles. At the prometamorphic stage, xCIRP2 protein is expressed in fibroblast, epidermal, nerve, and muscular cells and localized in their cytoplasm. When spontaneous metamorphosis progressed, the level of xCIRP2 mRNA remained unchanged but the amount of the protein decreased. In organ cultures of tails at the prometamorphic stage, xCIRP2 protein decreased before their lengths shortened during TH-dependent metamorphosis. The inhibition of calpain or proteasome attenuated the TH-induced decrease of xCIRP2 protein in tails, impairing their regression. These results suggest that xCIRP2 protein is downregulated through calpain- and proteasome-mediated proteolysis in response to TH at the onset of metamorphosis, inducing apoptosis in tails and thereby degenerating them.
⺠xCIRP2 is localized in the cytoplasm of multiple cells in tadpole tails. ⺠The xCIRP2 decrease occurs before the tail shortening during metamorphosis. ⺠xCIRP2 disappears through calpain- and proteasome-mediated proteolysis.
Journal: General and Comparative Endocrinology - Volume 179, Issue 1, 1 October 2012, Pages 14-21