Structural analysis of the proximal region of the microtubule-associated protein 1B promoter.
Structural analysis of the proximal region of the microtubule-associated protein 1B promoter.
复制标题
微管相关蛋白 1B 启动子近端区域的结构分析。
DOI：
10.1046/j.1471-4159.1997.69030910.x
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发表时间：
1997
影响因子：
4.7
通讯作者：
Fischer,I
中科院分区：
文献类型：
--
作者：
Liu,D;Fischer,I
微管相关蛋白 1B (MAP1B) 是神经系统发育早期表达的主要细胞骨架蛋白。之前对 MAP1B 基因的分析已经确定了两个可以独立调节 MAP1B 神经元特异性表达的替代启动子。为了进一步表征 MAP1B 启动子，我们在转录起始位点周围 8.5 kb 的范围内进行了体内 DNase I 超敏试验。这些研究发现，在 MAP1B 启动子的近端区域（位于两个转录起始位点之间），大脑中存在一个 DNase I 超敏位点，但肝细胞核中不存在该位点。通过 S1 核酸酶敏感性进行精细定位，定位到包含三个对称反向重复序列的近端启动子区域中的两个相邻位点。电泳迁移率变动分析表明，核提取物中存在的蛋白质可以结合近端启动子区域中存在的两个共有调控元件，即 Sp1 和环 AMP 响应元件。此外，两个常见序列（“神经元基序”和 TCC 重复基序）具有特定的核蛋白结合活性。这种结合活性在肝脏中比在脑核提取物中丰富得多，表明它可能代表 MAP1B 基因组织特异性表达的负控制元件。
Microtubule‐associated protein 1B (MAP1B) is a major cytoskeletal protein expressed early during development of the nervous system. Previous analysis of the MAP1B gene has identified two alternative promoters that can independently regulate neuron‐specific expression of MAP1B. To further characterize the MAP1B promoters, we performed DNase I hypersensitivity assays in vivo over a range of 8.5 kb surrounding the transcription initiation sites. These studies identified a DNase I‐hypersensitive site that was present in brain but not liver nuclei at the proximal region of the MAP1B promoter, located between the two transcription initiation sites. Fine mapping by S1 nuclease sensitivity localized two adjacent sites in the proximal promoter region that contained three symmetrical inverted repeats. Electrophoresis mobility shift assays showed that proteins present in nuclear extracts can bind two consensus regulatory elements present within the proximal promoter region, Sp1 and cyclic AMP response element. In addition, there was a specific nuclear protein binding activity with two common sequences, a “neuronal motif” and a TCC repeat motif. This binding activity was much more abundant in liver than in brain nuclear extracts, suggesting that it may represent a negative control element in the tissue‐specific expression of the MAP1B gene.