CELL-TYPE-SPECIFIC CONTACTS TO IMMUNOGLOBULIN ENHANCERS IN NUCLEI
CELL-TYPE-SPECIFIC CONTACTS TO IMMUNOGLOBULIN ENHANCERS IN NUCLEI
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DOI：
10.1038/313798a0
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发表时间：
1985-01-01
期刊：
影响因子：
64.8
通讯作者：
TONEGAWA, S
中科院分区：
文献类型：
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作者：
CHURCH, GM;EPHRUSSI, A;TONEGAWA, S
分隔活性免疫球蛋白基因的可变区和恒定区的内含子含有组织特异性转录增强子元件1 -3，DNA片段以方向和距离独立性（高达几个碱基（kb））方式顺式作用，以增强相邻启动子的转录起始4 -9。免疫球蛋白重链增强子仅在淋巴样细胞中有活性：在转染试验中，它能够控制猴病毒40（SV 40）T抗原、兔β-珠蛋白和免疫球蛋白基因启动子的顺式转录，距离至少2 kb 1 -3。遗传缺失分析表明，少至140个碱基对（bp）的区域足以增强效应1，2。这些功能特征和DNA序列在小鼠和人之间是保守的10 -15。然而，组织特异性蛋白质是否与增强子结合尚不清楚。在特定序列处与DNA相互作用的蛋白质可以阻止或增强单个鸟嘌呤或腺嘌呤与硫酸二甲酯（DMS）的反应16，并且该性质已被用于显示各种调节蛋白的DNA接触16 -26。在这里，我们将这种DMS策略应用于涉及使用基因组测序的完整哺乳动物细胞核内的单拷贝基因的实验中27。
The introns separating the variable and constant regions of active immunoglobulin genes contain tissue-specific transcriptional enhancer elements1–3, DNA segments which act in cis in an orientation and distanceindependent (up to a few kilobases (kb)) manner to enhance transcription initiation at adjacent promoters4–9. The immunoglobulin heavy-chain enhancer is active only in lymphoid cells: in transfection assays it is capable of controlling in cis transcription from the simian virus 40 (SV40) T-antigen, rabbitβ-globin and immunoglobulin gene promoters up to at least 2 kb away1–3. Genetic deletion analysis suggests that a region of as few as 140 base pairs (bp) is sufficient for the enhancement effect1,2. These functional characteristics and DNA sequences are conserved between mouse and man10–15. However, it is riot known whether tissue-specific proteins bind to the enhancer. Proteins that interact with DNA at specific sequences can prevent or enhance the reactions of individual guanines or adenines with dimethyl sulphate (DMS)16, and this property has been used to display the DNA contacts of various regulatory proteins16–26. Here we apply this DMS strategy in experiments involving single-copy genes within intact mammalian nuclei using genomic sequencing27.