Detection of an altered DNA conformation at specific sites in chromatin and supercoiled DNA.
Detection of an altered DNA conformation at specific sites in chromatin and supercoiled DNA.
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检测染色质和超螺旋 DNA 中特定位点的 DNA 构象改变。
DOI：
10.1073/pnas.80.14.4389
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发表时间：
1983
影响因子：
11.1
通讯作者：
Weintraub,H
中科院分区：
文献类型：
--
作者：
Kohwi-Shigematsu,T;Gelinas,R;Weintraub,H
我们发现，溴乙醛选择性地作用于未配对的腺嘌呤的N-1和N-6位以及未配对的胞嘧啶残基的N-3和N-4位，与完整细胞中的染色体DNA在活性基因附近的可能调控序列上发生反应。鸡βA-珠蛋白基因5‘端约200个碱基对，包含对核酸酶S1、几种限制性内切酶和非常低水平的DNase I敏感的部位，也包含对溴乙醛优先敏感的DNA结构。这些改变的DNA结构被发现在相对于βA-珠蛋白基因的可复制位置，无论溴乙醛是呈现给完整的红细胞、红细胞核，还是以纯化的超螺旋DNA的形式在pBR322中携带的βA-珠蛋白基因本身。与成人βA-珠蛋白不同，在表达胚胎β-珠蛋白的胚胎红细胞中不能检测到成人红细胞中与成人βA-珠蛋白基因不配对的DNA。我们的结果表明，DNA的明确区域与有效的不配对的碱基存在于完整的核中，这些结构对于特定的识别可能是重要的，因为它们是组织特异性的，并且在假定的调节区中被发现。
We show that bromoacetaldehyde, which reacts selectively at the N-1 and N-6 positions of unpaired adenine and at the N-3 and N-4 positions of unpaired cytosine residues reacts with chromosomal DNA in intact cells at probable regulatory sequences near active genes. A region of about 200 base pairs 5' to the chicken beta A-globin gene, which contains sites sensitive to nuclease S1, to several restriction endonucleases, and to very low levels of DNase I, also contains DNA structures that are preferentially sensitive to bromoacetaldehyde. These altered DNA structures are found at reproducible positions relative to the beta A-globin gene regardless of whether the bromoacetaldehyde is presented to intact erythrocytes, erythrocyte nuclei, or the beta A-globin gene itself carried in pBR322 as purified supercoiled DNA. The unpaired DNA 5' to the adult beta A-globin gene in adult erythrocytes is not detectable in embryonic erythrocytes that express embryonic beta-globin in contrast to adult beta A-globin. Our results suggest that well-defined regions of DNA with effectively unpaired bases occur in intact nuclei and that these structures may be important for specific recognition because they are tissue specific and are found at putative regulatory regions.