Sp1 and C/EBP-related factor regulate the transcription of human Cu/Zn SOD gene
Sp1 and C/EBP-related factor regulate the transcription of human Cu/Zn SOD gene
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DOI：
10.1016/0378-1119(96)00383-6
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发表时间：
1996-10-31
期刊：
影响因子：
3.5
通讯作者：
Jung, G
中科院分区：
文献类型：
--
作者：
Seo, SJ;Kim, HT;Jung, G
Cu/Zn超氧化物歧化酶（SOD 1）是保护细胞免受氧化应激的关键酶之一。它催化超氧自由基（O-2（-））歧化为氧和过氧化氢。为了研究人Cu/Zn SOD基因的转录调节，我们首先分析该基因的1.5-kb上游区域（参见Kim等人，1994年）。核苷酸（nt）-116 ~-45的元件可提高Cu/Zn SOD的转录活性。DNA酶I足迹法和电泳迁移率变动分析（EMSA）结果表明，Sp1与nt-104 ~-89区域结合，C/EBP相关因子与nt-64 ~-55区域结合。使用该启动子的两种突变形式，其中Spl和C/EBP相关因子结合位点分别被删除的研究表明，Spl和C/EBP相关因子激活SOD 1基因的转录。Sp1表达质粒pPacSp 1刺激SOD 1连接的CAT表达。C/EBP α表达载体pMSV-C/EBP共转染第116 ~ 45位核苷酸的元件后，HepG 2细胞中Cu/Zn SOD的转录活性增加，而HeLa细胞中Cu/Zn SOD的转录活性几乎没有增加。由于Sp1是一种普遍表达的转录因子，Sp1与Cu/Zn SOD近端上游区域的结合可能解释了Cu/Zn SOD在多种细胞中的表达。
The Cu/Zn superoxide dismutase (SOD1) is one of the key enzymes that protect cells against oxidative stress. It catalyzes the dismutation of superoxide radicals (O-2(-)) to oxygen and hydrogen peroxide. To study the transcriptional regulation of the human Cu/Zn SOD gene, we began by analyzing the 1.5-kb upstream region of the gene (see Kim et al., 1994). The element from nucleotides (nt) -116 to -45 increased the transcriptional activity of Cu/Zn SOD. Analyses by DNase I footprinting and electrophoretic mobility shift assay (EMSA) showed that Sp1 binds to the region from nt -104 to -89 and C/EBP-related factors to the region from nt -64 to -55. Studies using two mutant versions of this promoter, in which the Spl and C/EBP-related factor binding sites were deleted, respectively, revealed that Sp1 and C/EBP-related factors activate the transcription of SOD1 gene. An Sp1 expression plasmid, pPacSp1, stimulated the SOD1-linked CAT expression. Cotransfection of the element from nt -116 to -45 with the C/EBP alpha expression vector, pMSV-C/EBP, increased the transcriptional activity of the Cu/Zn SOD in HepG2 cells, but barely in HeLa cells. Because Sp1 is a ubiquitously expressed transcriptional factor, the binding of Sp1 to the proximal upstream region of the Cu/Zn SOD might explain the expression of Cu/Zn SOD in a wide variety of cells.