Starr R G, Lu B, Federoff H J
Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461.
Brain Res. 1994 Feb 28;638(1-2):211-20. doi: 10.1016/0006-8993(94)90652-1.
GAP-43 is a highly conserved neuronal protein whose expression is spatially and temporally regulated. Because this regulation may occur, at least in part, at the level of transcription, we have begun to characterize the regions upstream of the GAP-43 transcription unit which direct its neuronal-specific expression. Functional analyses of GAP-43 promoter-reporter constructs have been performed in stably transfected cell lines, including PC12, C6 and RAT2. These data indicate that as little as 600 bp of GAP-43 5'-flanking DNA sequence directs the expression in a neuronal-specific manner. A shorter construct containing 230 bp of 5'-flanking DNA sequence defines a GAP-43 minimal promoter that is active in both neuronal and glial but not in non-neural cell lines. An upstream region, previously shown by other investigators to have promoter activity, was able to stimulate transcription when linked to the downstream minimal promoter. However, this upstream region was by itself unable to direct transcription of the reporting gene. In addition, we have demonstrated that two polypurine tracts within the 5'-flanking DNA sequence of the GAP-43 gene adopt a non-duplex configuration in plasmids, and, when studied in the context of chromosomal integration, these regions have a stimulatory effect on transcription.
生长相关蛋白43（GAP - 43）是一种高度保守的神经元蛋白，其表达在空间和时间上受到调控。由于这种调控至少部分可能发生在转录水平，我们已开始对GAP - 43转录单元上游指导其神经元特异性表达的区域进行表征。已在稳定转染的细胞系（包括PC12、C6和RAT2）中对GAP - 43启动子 - 报告基因构建体进行了功能分析。这些数据表明，仅600 bp的GAP - 43 5'侧翼DNA序列就能以神经元特异性方式指导表达。一个包含230 bp 5'侧翼DNA序列的较短构建体定义了一个GAP - 43最小启动子，它在神经元和神经胶质细胞系中均有活性，但在非神经细胞系中无活性。先前其他研究人员已证明具有启动子活性的一个上游区域，当与下游最小启动子相连时能够刺激转录。然而，该上游区域自身无法指导报告基因的转录。此外，我们已证明GAP - 43基因5'侧翼DNA序列中的两个聚嘌呤区段在质粒中呈现非双链构象，并且在染色体整合的背景下进行研究时，这些区域对转录具有刺激作用。
