Abstract
LyGDI inhibits the dissociation of GDP from Rho family GTPases and is found in abundance in hematopoietic cells (1, 2). Here we report truncation of LyGDI as a biological indicator for mice irradiated in whole body. Two LyGDI fragments, 21-kDa and 17-kDa truncated products, accumulated in thymus of the exposed mice at peak quantities between 5 and 12 h after irradiation at doses exceeding 1 Gy. The truncated 17-kDa fragment of LyGDI was constitutively expressed in thymus of non-irradiated mice, but its decreased expression levels were found in mice irradiated with extremely low doses. These data demonstrate that regulation of Rho family GTPases by LyGDI is perturbed during thymic apoptosis, suggesting that fragmentation of LyGDI is a useful biological indicator to detect animals who had exposed with ionizing radiation even at low doses.
This work was partly supported by the Japan Atomic Energy Research Institute. To Drs. Masao Inoue and Osamu Nikaido, we wish to express our deep appreciation of their encouragement. We are grateful for the expert patent application assistance of Mr. Kensuke Matsumoto.
1. Ota, T., Maeda, M., Suto, S., and Tatsuka, M. Mol Carcinog, 39: 206-220, 2004.
2. Zhou, X., Suto, S., Ota, T., and Tatsuka, M. Radiat Res, 162: 287-295, 2004.
