通过纯化的SV40病毒粒子解离获得的含组蛋白核蛋白复合物中核小体的缺失。

Absence of nucleosomes in a histone-containing nucleoprotein complex obtained by dissociation of purified SV40 virions.

作者信息

Moyne G, Harper F, Saragosti S, Yaniv M

出版信息

Cell. 1982 Aug;30(1):123-30. doi: 10.1016/0092-8674(82)90018-6.

Abstract

Reduction of disulfide bonds involving the major capsid protein with dithiothreitol and removal of the calcium ions by EGTA disrupts the simian virus 40 virions. This process yields normal circular viral minichromosomes containing the four core histones and traces of the capsid proteins at pH values higher than 8.5. However, when carried out at pH 7.5, this procedure yields nucleoprotein complexes that contain both histones and the viral structural proteins. These pH 7.5 complexes appear as circular structures with a mean of 93 +/- 17 beads with a diameter of 7 nm and no visible nucleosomes when observed by electron microscopy. In contrast to the compaction of the viral DNA in minichromosomes, the length of these beaded structures is roughly the same as free DNA. We suggest that VP1, the major capsid protein, can act as a nucleosome unfolding agent in neutral pH and low ionic strength.

摘要

用二硫苏糖醇还原涉及主要衣壳蛋白的二硫键，并通过乙二醇双四乙酸（EGTA）去除钙离子，会破坏猴病毒40（Simian virus 40）病毒粒子。在pH值高于8.5时，这个过程会产生含有四种核心组蛋白和痕量衣壳蛋白的正常环状病毒微型染色体。然而，当在pH 7.5条件下进行时，此程序会产生同时包含组蛋白和病毒结构蛋白的核蛋白复合物。通过电子显微镜观察，这些pH 7.5的复合物呈现为平均有93±17个直径为7纳米的珠子的环状结构，且没有可见的核小体。与微型染色体中病毒DNA的压缩情况相反，这些串珠状结构的长度与游离DNA大致相同。我们认为，主要衣壳蛋白VP1在中性pH和低离子强度下可作为核小体解折叠剂。