Astrocyte heterogeneity revealed by expression of a GFAP-LacZ transgene
Astrocyte heterogeneity revealed by expression of a GFAP-LacZ transgene
复制标题
DOI：
10.1002/glia.20320
复制
发表时间：
2006-05-01
期刊：
影响因子：
6.2
通讯作者：
Brenner, M
中科院分区：
文献类型：
--
作者：
Lee, Y;Su, M;Brenner, M
胶质细胞酸性蛋白（GFAP）是一种主要存在于星形胶质细胞中的中间丝蛋白。该基因首先在星形胶质细胞成熟时表达，并且在成人中响应于CNS损伤而强烈上调。因此，除了其星形胶质细胞特异性，GFAP基因的转录调控作为发育和损伤期间CNS信号传导的报告者是令人感兴趣的。几个实验室已经表明，人或小鼠GFAP基因的约2kb的5-侧翼DNA足以将转基因表达导向星形胶质细胞并赋予发育和损伤诱导的调节。增强子区域已被确定为邻近基础启动子和RNA起始位点上游约1500 bp。这两个片段的并置产生了一个447 bp的启动子，gfa 28，它强烈驱动转染的胶质瘤细胞中的报告活性。我们在这里报告说，在小鼠gfa 28-lacZ转基因表达仅在某些脑区，揭示了一个意想不到的异质性之间的星形胶质细胞。限制性表达模式存在于发育早期，不因损伤而改变，并保存在培养的星形胶质细胞中。然而，从非活性区域培养的星形胶质细胞强烈表达瞬时转染的gfa 28-lacZ构建体，并且嵌入的gfa 28-lacZ转基因的活性通过用组蛋白脱乙酰酶抑制剂处理而部分恢复。这些结果表明，缺乏gfa 28-lacZ表达的特定脑区的结果，从一个发育失败，重塑GFAP染色质的开放结构。因此，gfa 28-lacZ转基因的表达似乎意外地标记了一组不同的星形胶质细胞前体。(c)2006 Wiley-Liss，Inc.
Glial fibrillary acidic protein (GFAP) is an intermediate filament protein present primarily in astrocytes. The gene is first expressed as astrocytes mature, and in the adult is strongly upregulated in response to CNS damage. Thus, in addition to its astrocyte specificity, transcriptional regulation of the GFAP gene is of interest as a reporter of CNS signaling during development and injury. Several laboratories have shown that approximately 2 kb of 5-flanking DNA of the human or mouse GFAP gene is sufficient to direct transgene expression to astrocytes and to confer developmental and injury-induced regulation. Enhancer regions have been identified adjacent to the basal promoter and about 1500 bp upstream of the RNA start site. Juxtaposition of these two segments yielded a 447 bp promoter, gfa28, which strongly drove reporter activity in transfected glioma cells. We report here that in mice a gfa28-lacZ transgene expresses in only certain brain regions, revealing an unexpected heterogeneity among astrocytes. The restricted pattern of expression is present early in development, is not altered by injury, and is preserved in cultured astrocytes. However, astrocytes cultured from an inactive region strongly express a transiently transfected gfa28-lacZ construct, and activity of the embedded gfa28-lacZ transgene is partially restored by treatment with a histone deacetylase inhibitor. These results indicate that the absence of gfa28-lacZ expression in specific brain regions results from a developmental failure to remodel GFAP chromatin to an open structure. Thus, expression of the gfa28-lacZ transgene appears to serendipitously mark a distinct set of astrocyte precursors. (c) 2006 Wiley-Liss, Inc.