Ponder B A, Crew F, Crawford L V
J Virol. 1978 Jan;25(1):175-86. doi: 10.1128/JVI.25.1.175-186.1978.
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.
我们用微球菌核酸酶和DNA酶I消化了从破碎病毒颗粒中分离出的多瘤病毒核蛋白复合物。将结果与从小鼠细胞核中提取的染色质消化结果进行了比较。核小体“核心”结构相似，但分离出的多瘤病毒核蛋白复合物中核小体的间距不规则，而在小鼠染色质中则是规则的。每种情况下核小体的平均重复长度为190至200个碱基对。这个数字表明，除非存在大量游离DNA，多瘤病毒核蛋白复合物包含约26个核小体。常用的在pH 10.2条件下通过破碎病毒颗粒制备核蛋白复合物的方法可能会对结构造成显著破坏。与沉降速度和浮力密度等常用标准相比，DNA对核酸酶消化的敏感性可能更清楚地揭示这种破坏。
