Identification of cis- and trans-acting factors regulating the expression of the human insulin receptor gene.
Identification of cis- and trans-acting factors regulating the expression of the human insulin receptor gene.
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调节人胰岛素受体基因表达的顺式和反式作用因子的鉴定。
DOI：
10.1016/s0021-9258(18)42881-5
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
S. Tsai
中科院分区：
文献类型：
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作者：
J. K. Lee;J. Tam;M. Tsai;S. Tsai
通过缺失突变和蛋白- dna相互作用研究，分析了人胰岛素受体（hIR）启动子的功能组织。一系列缺失突变体在两种人肝细胞HepG2和PLC中短暂表达。结果表明-692 ~ -345之间的启动子区域对hIR基因的高效转录至关重要。通过带移和足迹分析，确定了多个交互作用因素。Sp1绑定到一组GC盒和两个位于-637至-594的GGGAGG六聚体。在GC盒附近，有两个区域，从-550到-530和从-522到-503，它们结合两个新的因子，IRNF-I和IRNF-II。这两个因子在不同细胞系中的分布是不同的。GC、GA盒或irnf - 1结合位点上的连接子扫描突变显著降低了转录活性，表明irnf - 1和Sp1对hIR启动子活性很重要。此外，我们证明了体内hIR mRNA的糖皮质激素依赖性转录诱导是由hIR启动子中的糖皮质激素反应元件赋予的。综上所述，这些结果表明人类胰岛素受体基因的转录是由多个蛋白质- dna相互作用调控的，这些相互作用发生在定义的启动子区域内。
The functional organization of the human insulin receptor (hIR) promoter was analyzed by deletion mutagenesis and protein-DNA interaction studies. A series of deletion mutants was expressed transiently in two human hepatocytes, HepG2 and PLC. The results revealed that the promoter region between -692 and -345 is essential for efficient transcription of the hIR gene. Multiple trans-acting factors were identified by band shift and footprinting analyses. Sp1 binds to a cluster of GC boxes and two GGGAGG hexamers locating at -637 to -594. Adjacent to GC boxes, there are two regions, from -550 to -530 and from -522 to -503, which bind to two novel factors, IRNF-I and IRNF-II. These two factors are distributed differentially in different cell lines. Linker scanning mutations on GC, GA boxes, or the IRNF-I binding site significantly decreased the transcriptional activity, indicating that IRNF-I and Sp1 are important for hIR promoter activity. In addition, we demonstrated that glucocorticoid-dependent transcriptional induction of hIR mRNA in vivo is conferred by a glucocorticoid response element in the hIR promoter. Taken together, these results imply that transcription of the human insulin receptor gene is regulated by multiple protein-DNA interactions occurring within the defined promoter region.