Cationic metal-specific structures adopted by the poly(dG) region and the direct repeats in the chicken adult beta A globin gene promoter.
Cationic metal-specific structures adopted by the poly(dG) region and the direct repeats in the chicken adult beta A globin gene promoter.
复制标题
鸡成体 β A 珠蛋白基因启动子中的聚 (dG) 区域和同向重复序列采用的阳离子金属特异性结构。
DOI：
10.1093/nar/17.12.4493
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发表时间：
1989
影响因子：
14.9
通讯作者：
Kohwi,Y
中科院分区：
文献类型：
--
作者：
Kohwi,Y
分析了鸡成体βAglobin基因启动子中天然存在的连续脱氧鸟嘌呤残基及其周围序列在超螺旋质粒DNA中采用非B DNA结构的固有潜力。特别地，通过在Mg++、Cu++、Zn++、Ca++或Co++离子存在下用未配对的DNA碱基特异性探针氯乙醛处理含有鸡成年βAglobin 5′侧翼序列的超螺旋质粒DNA，研究了阳离子对结构的影响。通过化学切割方法，在单碱基分辨率下绘制氯乙醛反应性碱基，所述化学切割方法特异性地切割氯乙醛修饰位点处的DNA。这些实验表明，虽然Mg++和Ca++离子在相邻的dG残基处诱导dG-dG-dC三螺旋结构，但Zn++、Cu++和Co++离子在紧邻dG残基5'的同向重复序列处诱导另一种结构。当Mg++和Zn++同时存在时，Zn++抑制相邻dG残基处的dG-dG-dC三链体，并诱导相邻同向重复序列处的特定非B DNA结构。金属离子在启动子区域内的两个相邻序列处特异性诱导非B DNA结构可能具有生物学意义。
Naturally occurring contiguous deoxyguanine residues and their surrounding sequences in the chicken adult βAglobin gene promoter were analyzed for their inherent potential to adopt non-B DNA structures in supercoiled plasmid DNA. In particular, cationic effects on structure were studied by treating the supercoiled plasmid DNA harboring the chicken adult βAglobin 5′ flanking sequence with an unpaired DNA base-specific probe, chloroacetaldehyde in the presence of either Mg++, Cu++, Zn++, Ca++or Co++ions. The chloroacetaldehyde-reactive bases were mapped at a single base resolution by a chemical cleavage method that specifically cleaves DNA at the chloroacetaldehyde modified sites. These experiments revealed that while Mg++and Ca++ions induce a dG-dG-dC triple helix structure at the contiguous dG residues, Zn++, Cu++and Co++ions induce yet another structure at the direct repeats immediately 5' of the dG residues. When Mg++and Zn++ions are both present, Zn++inhibits the dG-dG-dC triplex at the contiguous dG residues and induces a particular non-B DNA structure at the adjacent direct repeats. The specific induction of non-B DNA structures by metal ions at the two adjacent sequences within the promoter region may be of biological significance.