ISOLATION OF Z-DNA BINDING-PROTEINS FROM SV40 MINICHROMOSOMES - EVIDENCE FOR BINDING TO THE VIRAL CONTROL REGION
ISOLATION OF Z-DNA BINDING-PROTEINS FROM SV40 MINICHROMOSOMES - EVIDENCE FOR BINDING TO THE VIRAL CONTROL REGION
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DOI：
10.1016/s0092-8674(85)80009-x
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发表时间：
1985-01-01
期刊：
影响因子：
64.5
通讯作者：
RICH, A
中科院分区：
文献类型：
--
作者：
AZORIN, F;RICH, A
测试通过增加NaCl浓度从SV 40微型染色体解离的蛋白质与Z-DNA [Br-聚（dG-dC）]和B-DNA [聚（dG-dC）]的结合。Z-DNA结合蛋白在0.2 M NaCl中大量释放，而大多数B-DNA结合蛋白直到0.6 M NaCl才释放。SV 40微型染色体与Z-DNA-Sephadex在低盐溶液中孵育产生具有Z-DNA结合活性的蛋白质（PZ蛋白）。这些蛋白质结合到含有左手Z-DNA的负超螺旋DNA种类，但不结合到松弛的DNA种类。它们与抗Z-DNA抗体竞争结合负超螺旋DNA种类。与其他质粒相比，与负超螺旋SV 40 DNA的结合更紧密，表明序列特异性Z-DNA结合。PZ蛋白与负超螺旋SV 40 DNA结合，干扰病毒控制区72个碱基对重复序列内SphI位点的裂解，但不干扰复制起点BglI位点的裂解。去除PZ蛋白也暴露了SV 40微型染色体中的SphI位点，而添加PZ蛋白使该位点不可接近。
Proteins dissociated from SV40 minichromosomes by increasing NaCl concentration were tested for their binding to Z-DNA [Br-poly(dG-dC)] and B-DNA [poly(dG-dC)]. Z-DNA binding proteins are largely released in 0.2 M NaCl whereas most B-DNA binding proteins are not released until 0.6 M NaCl. Incubation of SV40 minichromosomes with Z-DNA-Sephadex in low salt solution results in proteins with Z-DNA binding activity (PZ proteins). These proteins bind to negatively supercoiled DNA species containing left-handed Z-DNA but not to relaxed DNA species. They compete with anti-Z-DNA antibodies in binding to negatively supercoiled DNA species. The binding is tighter to negatively supercoiled SV40 DNA than to other plasmids, suggesting sequence-specific Z-DNA binding. PZ proteins binding to negatively supercoiled SV40 DNA interfere with cleavage at the SphI sites, within the 72 base pair repeat sequences of the viral control region, but not with cleavage at the BglI site, at the origin of replication. Removal of PZ proteins also exposes the SphI sites in the SV40 minichromosomes while addition of PZ proteins makes the sites inaccessible.