IDENTIFICATION OF AN INTERNAL CIS-ELEMENT ESSENTIAL FOR THE HUMAN L1 TRANSCRIPTION AND A NUCLEAR FACTOR(S) BINDING TO THE ELEMENT
IDENTIFICATION OF AN INTERNAL CIS-ELEMENT ESSENTIAL FOR THE HUMAN L1 TRANSCRIPTION AND A NUCLEAR FACTOR(S) BINDING TO THE ELEMENT
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DOI：
10.1093/nar/20.12.3139
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发表时间：
1992-06-25
影响因子：
14.9
通讯作者：
SAKAKI, Y
中科院分区：
文献类型：
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作者：
MINAKAMI, R;KUROSE, K;SAKAKI, Y
L1(Line-1)是源自反转录转座子的长的散布重复序列。以CAT基因为报告基因的转染研究表明，人L1序列的前155bp含有一个负责HeLa细胞启动子活性的元件(S)。转录从转基因中L1序列的第一个核苷酸开始。通过DNasel足迹分析，在L1序列的5‘端发现了三个显著的核蛋白结合位点。其中一个结合位点A位于+3到+26，是L1转录所必需的，因为A位点的突变导致启动子活性几乎完全丧失。A位点+11~+19的AAGATGGCC序列被定义为蛋白质结合的靶核心元件。A位点结合蛋白(命名为TFL1-A)存在于包括胚胎畸胎癌细胞系在内的多种细胞中。这些结果表明，位于L1序列非常5‘端的一个内部短元件和与该元件结合的核因子在人类L1的转录中起着至关重要的作用。
L1 (LINE-1) is a long interspersed repetitive sequence derived from a retrotransposon. Transfection studies using the CAT gene as a reporter demonstrated that the first 155bp in the human L1 sequence contains an element(s) responsible for the promoter activity in HeLa cells. The transcription was shown to initiate at the first nucleotide of the L1 sequence in the transgene. Three prominent nuclear protein binding sites were found in the 5' region of the L1 sequence by DNasel footprint analysis. One of the binding sites, designated as site A located at + 3 to + 26, was shown to be essential for the L1 transcription because the mutation at the site A caused almost complete loss of the promoter activity. A sequence AAGATGGCC at + 11 to + 19 in the site A was defined as a target core element for the protein binding. The site A - binding protein (designated TFL1-A) was found in various types of cells including an embryonic teratocarcinoma cell line. These results indicate that an internal short element located at the very 5' terminal of L1 sequence and the nuclear factor binding to the element play a crucial role in the transcription of human L1.