BIOLOGICAL SIGNIFICANCE OF UNWINDING CAPABILITY OF NUCLEAR MATRIX ASSOCIATING DNAS
BIOLOGICAL SIGNIFICANCE OF UNWINDING CAPABILITY OF NUCLEAR MATRIX ASSOCIATING DNAS
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DOI：
10.1126/science.1553545
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发表时间：
1992-01-10
期刊：
影响因子：
56.9
通讯作者：
KOHWISHIGEMATSU, T
中科院分区：
文献类型：
--
作者：
BODE, J;KOHWI, Y;KOHWISHIGEMATSU, T
基质附着区（MARs）被认为是将染色质分离成拓扑约束的环状结构域。位于人β-干扰素基因5'端的MAR在超螺旋张力下变成稳定的碱基不配对，免疫球蛋白重链基因增强子侧翼的MAR也是如此;在这两种情况下，都存在DNA解旋的成核位点。含有解旋成核位点的多联体寡核苷酸在稳定的转化体中表现出对核支架的强亲和力和增强的SV 40启动子活性。突变的多联体寡核苷酸抵抗解旋，表现出弱亲和力的核支架，并没有提高启动子活性。这些结果表明，能够缓解超螺旋应变的DNA功能是重要的MAR功能。
Matrix attachment regions (MARs) are thought to separate chromatin into topologically constrained loop domains. A MAR located 5' of the human beta-interferon gene becomes stably base-unpaired under superhelical strain, as do the MARs flanking the immunoglobulin heavy chain gene enhancer; in both cases a nucleation site exists for DNA unwinding. Concatemerized oligonucleotides containing the unwinding nucleation site exhibited a strong affinity for the nuclear scaffold and augmented SV40 promoter activity in stable transformants. Mutated concatemerized oligonucleotides resisted unwinding, showed weak affinity for the nuclear scaffold, and did not enhance promoter activity. These results suggest that the DNA feature capable of relieving superhelical strain is important for MAR functions.