Analysis on the function of a protein encoded by a thyroid hormone responsive gene, ZAKI-4, in order to elucidate the molecular mechanizm of thyroid hormone action on brain development

分析甲状腺激素反应基因ZAKI-4编码蛋白的功能，阐明甲状腺激素对大脑发育作用的分子机制

基本信息

批准号：
11470225
负责人：
MURATA Yoshiharu
金额：
$ 7.42万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

It is well known that thyroid hormone (T_3) plays a pivotal role in brain development, however, its molecular mechanism remains to be elucidated. We previously identified a thyroid hormone-responsive gene, ZAKI-4. ZAKI-4 encodes a protein (ZAKI-4 protein) with a molecular mass of 26kd. Recently, it has been reported that ZAKI-4 belongs to a family protein that inhibits calcineurin activity in vivo. Sicne calcineurin is known to play important roles in brain development and function, we hypothesized, that ZAKI-4 protein is one of key factors to mediate T_3 action during brain development and designed the present research projects to elucidate the in vivo function of ZAKI-4 protein. For this purpose we tried to produce mice in which the expression of ZAKI-4 is completely eliminated. As the first step to knockout ZAKI-4 gene, we determined the genomic organization of mouse ZAKI-4 gene and a targeting vector was constructed. We are currently carrying out homologous recombination in embryon … More ic stem (ES) cells derived from a mouse train (129/Sv). In the present study, the spatial and ontogenic expression of ZAKI-4 mRNA and the effect of hypothyroidism on the expression were also examined in brain of rodents. In cerebral cortex, the expression of ZAKI-4 mRNA was observed as early as embryonic day 18 and the expression increased during the brain development. This increase was significantly blunted tn hypothyroid rats. On the other hand the expression was constant and was not affected by hypothyroidism in cerebellum. In situ hybridization revealed that ZAKI-4 mRNA was widely expressed in the entire brain. It was noted that ZAKI-4 was highly expressed in the area such as olfactory bulb, hipocampus, cerebral cortex and cerebellum, where calcineurin is abundt. These results demonstrated that the expression of ZAKI-4 mRNA was indeed regulated by thyroid status in vivo and would suggest that thyroid hormone excerts its biological function during brain development at least in part by regulating ZAKI-4 expression and thus by controling calcineruin activity. Less

众所周知，甲状腺马酮（T_3）在大脑发育中起关键作用，但是，其分子机制仍有待阐明。我们以前鉴定出甲状腺响应基因Zaki-4。 Zaki-4用分子质量为26KD编码蛋白（Zaki-4蛋白）。最近，据报道，Zaki-4属于一种抑制体内钙调蛋白活性的家族蛋白。我们假设，已知Sicne钙调蛋白在大脑发育和功能中起重要作用，Zaki-4蛋白是介导T_3在大脑发育过程中介导T_3作用的关键因素之一，并设计了目前的研究项目以阐明Zaki-4蛋白的体内功能。为此，我们试图产生Zaki-4表达的小鼠。作为敲除Zaki-4基因的第一步，我们确定了小鼠Zaki-4基因的基因组组织和靶向载体的构建。我们目前正在胚胎中进行同源重组……更多来自小鼠列（129/sv）的IC茎（ES）细胞。在本研究中，还检查了扎基-4 mRNA的空间和个体表达以及甲状腺功能减退症对表达的影响。在脑皮质中，早在胚胎第18天就观察到Zaki-4 mRNA的表达，并且表达增加了。在大脑发育期间。这种增加的甲状腺功能减退症显着钝化。另一方面，该表达是恒定的，并且不受小脑甲状腺功能减退症的影响。原位杂交表明，扎基-4 mRNA在整个大脑中广泛表达。值得注意的是，Zaki-4在诸如嗅球，Hipocampus，脑皮层和小脑等区域高度表达，那里是钙调神经素。这些结果表明，Zaki-4 mRNA的表达确实受到体内甲状腺状态的调节，并表明甲状腺激素在脑发育过程中至少通过调节Zaki-4的表达，从而通过控制钙化因素的活性来表达其在脑发育过程中的生物学功能。较少的