Molecular cell-biological studies on differentiation and mitotic arrest of brain neurons

脑神经元分化和有丝分裂停滞的分子细胞生物学研究

基本信息

批准号：
08458253
负责人：
YOSHIKAWA Kazuaki
金额：
$ 4.67万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

Neurons in the vertebrate central nervous system CNS withdraw permanently from the cell cycle immediately after differentiation from their proliferative progenitors. To study the molecular mechanism whereby neurons become postmitotic, we focused on the functional roles and molecular properties of necdin, a neuronal growth suppressor isolated from embryonal carcinoma P19 cells. Results obtained are as follows. [1] Necdin, like retinoblastoma protein (Rb), bound to transforming domains of simian virus 40 (SV40) large T antigen and adenovirus E1A.[2] Necdin bound to E2F-1, a cellular transcription factor that promotes the cell cycle, and suppressed its functions. [3] Ectopic expression of necdin in Rb-dificient SAOS-2 cells suppressed the cell growth, indicating that necdin is a functional substitute for Rb. [4] An antibody against recombinant necdin protein reacted with necdin in the cytoplasm of mouse brain neurons, and the immunoreactivity was the highest in the hypothalamus.[5] The 5'-end sequence of the human necdin gene contains frequent CpG dinucleotides (identified as a CpG island), and methylation in vitro of CpG dinucleotides in the promoter region suppressed the transcriptional activity. [6] The human necdin gene was localized to chromosome 15q11.2-q12, which lies within the region involved in Prader-Willi syndrome, a genomic imprinting-associated neurobehavioral disorder. [7] In summary, necdin suppresses cell growth in a manner similar to that of Rb, and its deficiency may cause the defect of neuronal differentiation.

脊椎动物中枢神经系统中的神经元在与增生性祖细胞分化后立即从细胞周期中永久退出。为了研究神经元变成有丝分裂的分子机制，我们专注于NECDIN的功能和分子特性，NECDIN是一种从胚胎癌P19细胞中分离出的神经元生长抑制剂。获得的结果如下。 [1] Necdin，就像视网膜细胞瘤蛋白（RB）一样，与转化邻苯二甲酸病毒40（SV40）大的T抗原和腺病毒E1A的结构域。[2] NECDIN与E2F-1结合，E2F-1是促进细胞周期并抑制其功能的细胞转录因子。 [3] NECDIN在RB剂量的SAOS-2细胞中的异位表达抑制了细胞的生长，表明NECDIN是RB的功能替代品。 [4]针对重组坏死蛋白的抗体与小鼠脑神经元的细胞质中反应，免疫反应性是下丘脑中最高的。[5]人NECDIN基因的5端序列含有频繁的CpG二核苷酸（被识别为CpG岛），并且在启动子区域中CpG二核苷酸的体外甲基化抑制了转录活性。 [6]人NECDIN基因被定位于15q11.2-Q12染色体，该基因位于Prader-Willi综合征中涉及的区域内，这是一种基因组烙印相关的神经行为疾病。 [7]总之，NECDIN以类似于RB的方式抑制细胞生长，其缺乏可能会导致神经元分化的缺陷。