Pederson D S, Venkatesan M, Thoma F, Simpson R T
Proc Natl Acad Sci U S A. 1986 Oct;83(19):7206-10. doi: 10.1073/pnas.83.19.7206.
A multicopy yeast plasmid containing the TRP1 gene (coding for N-5'-phosphoribosylanthranilate isomerase) and ARS1 (autonomously replicating sequence 1) has been purified as chromatin. Electrophoretic analysis of nucleic acid and proteins and electron microscopy show that the plasmid chromatin is largely free of contaminants. Electron-microscopic and linking-number analyses indicate that the plasmid chromatin contains seven nucleosomes, as predicted by the indirect end-label analyses of Thoma, Bergman, and Simpson [J. Mol. Biol. (1984) 177, 715-733]. Indirect end label mapping of micrococcal nuclease cuts demonstrates that nucleosome positions and nuclease-sensitive regions are not altered by the purification. The plasmid chromatin behaves homogeneously with respect to its elution from nuclei, template activity, and intrinsic buoyant density. Taken together, these observations suggest that different copies of the TRP1ARS1 plasmid do not differ from each other grossly in chromatin structure. We discuss the potential for understanding eukaryotic gene regulation offered by the ability to isolate unique genes as chromatin.
一种含有TRP1基因（编码N - 5'-磷酸核糖基邻氨基苯甲酸异构酶）和ARS1（自主复制序列1）的多拷贝酵母质粒已被纯化成染色质。核酸和蛋白质的电泳分析以及电子显微镜观察表明，该质粒染色质基本没有污染物。电子显微镜和连环数分析表明，该质粒染色质含有7个核小体，这与托马、伯格曼和辛普森的间接末端标记分析预测结果一致[《分子生物学杂志》（1984年）177卷，715 - 733页]。微球菌核酸酶切割的间接末端标记图谱表明，核小体位置和核酸酶敏感区域在纯化过程中未发生改变。该质粒染色质在从细胞核洗脱、模板活性和固有浮力密度方面表现出均一性。综上所述，这些观察结果表明，TRP1ARS1质粒的不同拷贝在染色质结构上彼此之间没有明显差异。我们讨论了将独特基因作为染色质分离的能力为理解真核基因调控所提供的潜力。
