The transcriptional repressor REST determines the cell-specific expression of the human MAPK8IP1 gene encoding IB1 (JIP-1)
The transcriptional repressor REST determines the cell-specific expression of the human MAPK8IP1 gene encoding IB1 (JIP-1)
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DOI：
10.1128/mcb.21.21.7256-7267.2001
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发表时间：
2001-11-01
影响因子：
5.3
通讯作者：
Waeber, G
中科院分区：
文献类型：
--
作者：
Abderrahmani, A;Steinmann, M;Waeber, G
胰岛-脑1(IB1)是人和大鼠JIP-1的同源物，JIP-1是与c-jun氨基末端激酶(JNK)相互作用的支架蛋白。IB1的表达主要局限于内分泌胰腺和中枢神经系统。在此，我们探讨了IB1这种优先的胰岛和神经元表达的转录机制。从人BAC文库中克隆了人MAPK81P1基因5‘调控区的731个核苷酸片段，并克隆到荧光素酶报告基因的上游。这种结构在胰岛素分泌细胞和神经元样细胞中都驱动了高转录活性，但在无关的细胞系中却没有。对该启动子区域的序列分析表明，存在一个神经元限制性沉默元件(NRSE)，该元件可结合阻遏蛋白锌指蛋白。该因子在胰岛素分泌细胞和神经元样细胞中不表达。通过迁移率改变分析，我们证实了REST与IB1启动子中存在的NRSE结合。一旦将编码REST的表达载体瞬时转染到β细胞系中，就会抑制IB1的转录活性。在IB1基因5‘调控区引入突变的NRSE，取消了在胰岛素分泌的β细胞中由REST驱动的抑制活性，并缓解了在无关细胞中观察到的IB1的低转录活性。此外，将编码REST转录抑制结构域缺失的表达载体转染到非β和非神经细胞系中，可减轻IB1启动子的活性。最后，Rest介导的对IB1的抑制可以被曲古菌素A取消，这表明需要去乙酰酶活性才能允许REST抑制。综上所述，这些数据确立了REST在控制人类IB1基因的组织特异性表达方面的关键作用。
Islet-brain 1 (IB1) is the human and rat homologue of JIP-1, a scaffold protein interacting with the c-jun amino-terminal kinase (JNK). IB1 expression is mostly restricted to the endocrine pancreas and to the central nervous system. Herein, we explored the transcriptional mechanism responsible for this preferential islet and neuronal expression of IB1. A 731-bp fragment of the 5' regulatory region of the human MAPK81P1 gene was isolated from a human BAC library and cloned upstream of a luciferase reporter gene. This construct drove high transcriptional activity in both insulin-secreting and neuron-like cells but not in unrelated cell lines. Sequence analysis of this promoter region revealed the presence of a neuron-restrictive silencer element (NRSE) known to bind repressor zinc finger protein REST. This factor is not expressed in insulin-secreting and neuron-like cells. By mobility shift assay, we confirmed that REST binds to the NRSE present in the IB1 promoter. Once transiently transfected in beta -cell lines, the expression vector encoding REST repressed IB1 transcriptional activity. The introduction of a mutated NRSE in the 5' regulating region of the IB1 gene abolished the repression activity driven by REST in insulin-secreting beta cells and relieved the low transcriptional activity of IB1 observed in unrelated cells. Moreover, transfection in non-beta and nonneuronal cell lines of an expression vector encoding REST lacking its transcriptional repression domain relieved IB1 promoter activity. Last, the REST-mediated repression of IB1 could be abolished by trichostatin A, indicating that deacetylase activity is required to allow REST repression. Taken together, these data establish a critical role for REST in the control of the tissue-specific expression of the human IB1 gene.