Study of DNA repair deficient mice

DNA修复缺陷小鼠的研究

基本信息

批准号：
10044231
负责人：
YASUI Akira
金额：
$ 4.48万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

We isolated two mouse homologues of photolyase gene (mCry1 and mCry2), which encode proteins in the family of blue-light receptors. To explore the biological function of mammalian Cry1 and Cry2, we have generated cry1 and cry2 mutant mice through gene targeting in embryonic stem cells. Since these mutant mice are completely healthy and showed no overt phenotype, we analyzed the possible role for CRY proteins in the biological clock by measuring the circadian wheel-running behavior of cry-knockout mice under normal light/dark (LD) cycles and in constant darkness (DD). Since CRY proteins are able to function as blue-light receptor, these protein may be involved in the light entrainment ability. We found that mice lacking the Cry1 or Cry2 protein display accelerated and delayed free-running (DD) periodicity of locomotor activity, respectively. These findings suggest that Cry1 and Cry2 antagonistically modulate the period length of the clock. Above results indicate, however, that a deficiency in either gene does not produce a detectable loss of light entrainment of locomotor activity. Since cry1 mouse still contain a functional Cry2 protein, we generated double-mutant animals. To our surprise, in the absence of both proteins, an instantaneous and complete loss of free-running rhythmicity is observed. This suggests that, in addition to a possible photoreceptor and antagonistic clock-adjusting function, both proteins are essential for the maintenance of circadian rhytjmicity.

我们分离了光裂解酶基因的两个小鼠同源物（mCry1 和 mCry2），它们编码蓝光受体家族中的蛋白质。为了探索哺乳动物Cry1和Cry2的生物学功能，我们通过胚胎干细胞中的基因打靶产生了cry1和cry2突变小鼠。由于这些突变小鼠完全健康并且没有表现出明显的表型，我们通过测量cry-knockout小鼠在正常光/暗（LD）循环和恒定光照下的昼夜节律轮运行行为来分析CRY蛋白在生物钟中的可能作用。黑暗（DD）。由于 CRY 蛋白能够充当蓝光受体，因此这些蛋白可能与光夹带能力有关。我们发现缺乏 Cry1 或 Cry2 蛋白的小鼠分别表现出加速和延迟的自由奔跑（DD）周期性运动活动。这些发现表明 Cry1 和 Cry2 拮抗地调节时钟的周期长度。然而，上述结果表明，任一基因的缺陷都不会导致可检测到的运动活动的光夹带损失。由于cry1小鼠仍然含有功能性Cry2蛋白，我们产生了双突变动物。令我们惊讶的是，在缺乏这两种蛋白质的情况下，观察到自由运行的节律性瞬间完全丧失。这表明，除了可能的光感受器和拮抗性时钟调节功能之外，这两种蛋白对于维持昼夜节律性也是必需的。