ASTROCYTOSIS AND AXONAL PROLIFERATION IN THE HIPPOCAMPUS OF S100B TRANSGENIC MICE
ASTROCYTOSIS AND AXONAL PROLIFERATION IN THE HIPPOCAMPUS OF S100B TRANSGENIC MICE
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DOI：
10.1073/pnas.91.12.5359
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发表时间：
1994-06-07
影响因子：
11.1
通讯作者：
HILT, DC
中科院分区：
文献类型：
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作者：
REEVES, RH;YAO, JB;HILT, DC
S100 β是一种钙结合蛋白，主要由星形胶质细胞在大脑中高水平表达。将S100 β的二硫键二聚体形式添加到原代神经元和神经胶质培养物和已建立的细胞系中诱导轴突延伸和星形胶质细胞增殖和表型的改变，但尚未提出S100 β在体内发挥相同作用的证据。使用8.9 kb鼠S100 b基因组克隆产生两种转基因小鼠品系，其中S100 β RNA以剂量相关方式增加至正常水平的2倍和7倍。这些线显示整个大脑中伴随增加的S100 β蛋白。在这两个系中的表达是细胞类型和组织适当的，并且表达水平与转基因拷贝数相关，表明基因的正常调节所必需的序列包括在克隆片段内。在成年转基因小鼠的海马中，Western印迹检测到胶质细胞酸性蛋白和轴突发芽的几个标志物的水平升高，包括神经丝L，神经丝H和M的磷酸化表位，和β-微管蛋白。免疫细胞化学显示星形胶质细胞形态和轴突发芽的改变，特别是在齿状回。这些转基因小鼠为研究S100 β在正常发育和脑功能中神经胶质-神经元相互作用中的作用以及分析唐氏综合征和阿尔茨海默病中S100 β水平升高的意义提供了有用的模型。
S100 beta is a calcium-binding protein that is expressed at high levels in brain primarily by astrocytes. Addition of the disulfide-bonded dimeric form of S100 beta to primary neuronal and glial cultures and established cell lines induces axonal extension and alterations in astrocyte proliferation and phenotype, but evidence that S100 beta exerts the same effects in vivo has not been presented. An 8.9-kb murine S100b genomic clone was used to produce two lines of transgenic mice in which S100 beta RNA is increased in a dose-related manner to 2-fold and 7-fold above normal. These lines show concomitant increased S100 beta protein throughout the brain. Expression in both lines is cell type- and tissue-appropriate, and expression levels are correlated with the transgene copy number, demonstrating that sequences necessary for normal regulation of the gene are included within the cloned segment. In the hippocampus of adult transgenic mice, Western blotting detects elevated levels of glial fibrillary acidic protein and several markers of axonal sprouting, including neurofilament L, phosphorylated epitopes of neurofilament H and M, and beta-tubulin. Immunocytochemistry demonstrates alterations in astrocyte morphology and axonal sprouting, especially in the dentate gyrus. Thus, both astrocytosis and neurite proliferation occur in transgenic mice expressing elevated levels of S100P beta These transgenic mice provide a useful model for studies of the role of S100 beta in glial-neuronal interactions in normal development and function of the brain and for analyzing the significance of elevated levels of S100 beta in Down syndrome and Alzheimer disease.