权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

PHysiological roles and action Mechanisms of programd cell death in the brain during the ontogeny

生理作用和作用个体发育期间大脑程序性细胞死亡的机制

基本信息

批准号：
03804060
负责人：
MIWA Nobuhiko
金额：
$ 1.41万
依托单位：
HIROSHIMA PREFECTUAL UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

项目摘要

At a period of programd cell death, the neonatal mouse brain generates the killer glycoprotein NBCF(62 kDa, pI 9.1), which induced cell aggregation, pycnosis, and shrinkage of cytoplasm at the initial stage as typically observed for apoptosis, and double strand scission of nuclear DNA by 180-210 bp in human neuroblastoma NB1 cells by a NBCF-treatment time of 6 hr corresponding to a point of no return as shown by agarose gel electrophoresis. Cytolysis continued to proceed at 12-24 hr after NBCF addition, whereas degrees of intracelluar DNA scission ceased to increase at 12 hr and were similar to extracellular DNA scission degrees, suggesting that a limited degree of internucleosomal DNA scission is responsible for cytolysis. The DNA scission was inhibited with Zn or TPCK added at the initial stage, but not with cycloheximide initially added or with Zn or TPCK added after 6 hr, suggesting DNA scission by activation of preexisting endonuclease (EN) precursor but not by promotion of EN transcription. NB1 cells differentiated with a human glioblastoma A172 cell-derived defferentiation factor (36 kDa, pI 5.5) exhibited outgrowth of many neurites followed by reduced susceptibility to NBCF, and concurrently secreted a proteinic NBCF-antagonizing factor (43 kDa, basic), which transiently attenuated DNA scission degrees in undifferentiated NB1 cells treated with NBCF after a slight increase in DNA scission degrees initially observed, suggesting reversibility or tolerance in spoptosis. Isolated nuclei alone or together with cell homogenate or cell membrane of NB1 cells but not whole cells were saved from DNA scission by NBCF, showing that extracellular factors built in intact cells are essential for the DNA scission.

在细胞程序性死亡期间，新生小鼠大脑产生杀伤糖蛋白NBCF（62 kDa，pI 9.1），其在初始阶段诱导细胞聚集、固缩和细胞质收缩，如典型地观察到的凋亡，和NBCF-1在人神经母细胞瘤NB 1细胞中180-210 bp的核DNA双链断裂。处理时间为6小时，对应于琼脂糖凝胶电泳显示的不返回点。加入NBCF后12-24小时细胞溶解继续进行，而细胞内DNA断裂程度在12小时停止增加，与细胞外DNA断裂程度相似，表明有限程度的核小体间DNA断裂是细胞溶解的原因。在初始阶段加入Zn或TPCK抑制DNA断裂，但不与放线菌酮初始添加或与Zn或TPCK添加后6小时，表明DNA断裂通过激活预先存在的核酸内切酶（EN）前体，但不是通过促进EN转录。人胶质母细胞瘤A172细胞源分化因子诱导NB 1细胞分化的研究（36 kDa，pI 5.5）表现出许多神经突的生长，随后对NBCF的敏感性降低，并同时分泌蛋白质NBCF拮抗因子（43 kDa，碱性），在用NBCF处理的未分化的NB 1细胞中，在最初的DNA断裂程度轻微增加之后，观察到，这表明可逆性或耐受性在spoptosis。NBCF使分离的细胞核单独或与NB 1细胞的细胞匀浆或细胞膜一起而不是整个细胞免于DNA断裂，表明完整细胞中构建的细胞外因子对于DNA断裂是必需的。