Isolation and characterization of a gene encoding human Kruppel-like factor 5 (IKLF): binding to the CAAT/GT box of the mouse lactoferrin gene promoter
Isolation and characterization of a gene encoding human Kruppel-like factor 5 (IKLF): binding to the CAAT/GT box of the mouse lactoferrin gene promoter
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DOI：
10.1093/nar/27.24.4807
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发表时间：
1999-12-15
影响因子：
14.9
通讯作者：
Teng, CT
中科院分区：
文献类型：
--
作者：
Shi, HP;Zhang, ZP;Teng, CT
小鼠乳铁蛋白基因启动子包括一个CAAT/GT盒，GGGCAATAGGGTGGGGCCAGCCC，它在人子宫内膜癌RL 95 -2细胞（RL 95）中起表皮生长因子反应元件（EGFRE）的作用。在这项工作中，我们已经确定EGFREB编码Kruppel样因子5（KLF 5）的C-末端，该mRNA在人结肠和小肠中最丰富。以EGFREB为杂交探针，从人结肠文库中克隆了全长cDNA。该基因全长3336 bp，其中5 '-UTR为302 bp，3'-UTR为1663 bp，1371 bp，编码457个氨基酸。根据IKLF的组织分布和与小鼠IKLF的序列同源性，我们将其命名为IKLF。人IKLF基因长度跨度>20 kb，由4个外显子组成，其内含子/外显子连接遵循GT/AG规则。三个锌指由三个外显子编码。转染实验和Western分析中，绿色荧光蛋白（GFP）标记的IKLF被证实位于核内。IKLF在RL 95细胞中的过表达抑制了含有小鼠乳铁蛋白基因的CAAT/GT盒的报告构建体的活性。这些发现表明IKLF是一种与CAAT/GT盒结合的核转录因子，并作为小鼠乳铁蛋白基因启动子活性的调节剂发挥作用。
The mouse lactoferrin gene promoter includes a CAAT/GT box, GGGCAATAGGGTGGGGCCAGCCC, which functions as the epidermal growth factor response element (EGFRE) in human endometrial carcinoma RL95-2 cells (RL95), A positive clone, EGFREB, of 2575 bp length, was isolated from an expression library of RL95 cells with a multimer of the EGFRE sequence. In this work, we have identified that EGFREB encodes the C-terminus of Kruppel-like factor 5 (KLF5), This mRNA is most abundant in human colon and small intestine. A full-length cDNA clone was isolated from a human colon library using EGFREB as the hybridization probe. The full-length cDNA consists of 3336 bp with a 302 bp 5'-UTR, a 1663 bp 3'-UTR, and a 1371 bp sequence coding for a 457 amino acid polypeptide, Based on its tissue distribution and sequence homology to the mouse IKLF, we renamed this protein IKLF, DNase I footprinting and electrophoresis mobility shift assay confirmed the binding of IKLF to the EGFRE. The human IKLF gene spans >20 kb in length and is organized into four exons, whose intron/exon junctions follow the GT/AG rule. The three zinc fingers are encoded by three exons, Nuclear localization of IKLF was demonstrated by green fluorescence protein (GFP)-tagged IKLF in transfection experiments and western analysis. Overexpression of IKLF in RL95 cells represses the activity of reporter constructs containing the CAAT/GT box of the mouse lactoferrin gene. These findings imply that IKLF is a nuclear transcription factor that binds to the CAAT/GT box, and functions as a modulator of the mouse lactoferrin gene promoter activity.