Comparison of nuclease digestion of polyoma virus nucleoprotein complex and mouse chromatin
Comparison of nuclease digestion of polyoma virus nucleoprotein complex and mouse chromatin
复制标题
多瘤病毒核蛋白复合物和小鼠染色质的核酸酶消化比较
作者：
B. Ponder;F. Crew;L. Crawford
我们用微球菌核酸酶和 DNase I 消化了从破碎的病毒颗粒中分离出来的多瘤病毒核蛋白复合物。将结果与小鼠细胞核染色质的消化结果进行了比较。核小体“核心”结构相似，但分离的多聚瘤核蛋白复合物中核小体的间距不规则，而小鼠染色质中的核小体间距是规则的。每种情况下的平均核小体重复长度为 190 至 200 个碱基对。该图表明，除非存在大量游离 DNA，否则多瘤核蛋白复合物包含约 26 个核小体。常用的通过在 pH 10.2 下破坏病毒粒子来制备核蛋白复合物的方法可能会导致结构的严重损坏。 DNA 对核酸酶消化的敏感性可能比通常的沉降速度和浮力密度标准更清楚地揭示了这种损伤。
We digested polyoma virus nucleoprotein complex, isolated from disrupted virions, with micrococcal nuclease and DNase I. The results were compared with digestions of chromatin from mouse nuclei. The nucleosome "core" structures were similar, but the spacing of the nucleosomes in the isolated polymoma nucleoprotein complexes was irregular, whereas in mouse chromatin it was regular. The average nucleosome repeat length in each case was 190 to 200 base pairs. This figure suggests that, unless there are substantial stretches of free DNA, the polyoma nucleoprotein complex contains about 26 nucleosomes. The commonly used method of preparing the nucleoprotein complex by disruption of virions at pH 10.2 may lead to significant damage to the structure. Such damage may be more clearly revealed by the susceptibility of the DNA to nuclease digestion than by the usual criteria of sedimentation velocity and buoyant density.