SUBUNIT STRUCTURE OF CHROMATIN

这项研究的根本目的是定量地理解 核小体中DNA-组蛋白核心相互作用的稳定性。 这将通过研究(A)核小体滑动的动力学进行分析。 以及(B)核小体的解离平衡。解离 均衡将被解释为一个模型，该模型包括 组蛋白八聚体解离为六聚体、四聚体和二聚体 组蛋白。沉积平衡将被用来分析 组蛋白核心解离，并结合沉积平衡， 将采用沉降速度和凝胶电泳法进行 核小体解离研究。组蛋白乙酰化的影响将 使用富含修饰组蛋白的重组颗粒进行检测。 滑动过程将从两个方面进行分析。直接测量 克隆DNA上以阶段性方式重组的组蛋白核心的滑动 片断将被用来确定基本机理和基本原理 滑动率。核小体解离的动力学(似乎 涉及滑动机构)将使用圆二向色性进行研究 和/或一种新的电泳法。再一次，组蛋白的影响 对税率的修改将进行研究。 有证据表明，核小体的稳定性及其移位 DNA可能在DNA复制、修复等过程中起着重要作用 和抄写。因此，DNA-组蛋白的定量分析 互动对于全面理解这些过程可能是至关重要的 真核生物。

The fundamental objective of this research is a quantitative understanding of the stability of the DNA-histone core interaction in the nucleosome. This will be analyzed by studies of (a) the kinetics of nucleosome sliding on DNA, and (b) the dissociation equilibria of nucleosomes. Dissociation equilibria will be interpreted in terms of a model which includes the dissociation of the histone octamer into hexamers, tetramers and dimers of the histones. Sedimentation equilibrium will be used to analyze the histone core dissociation, and a combination of sedimentation equilibrium, sedimentation velocity and gel electrophoresis will be employed for the nucleosome dissociation studies. The effects of histone acetylation will be assayed, using reconstituted particles enriched in modified histones. The sliding process will be analyzed in two ways. Direct measurement of sliding of a histone core reconstituted in a phased fashion on a cloned DNA fragment will be used to determine the fundamental mechanism and basic sliding rate. The kinetics of nucleosome dissociation (which seems to involve a sliding mechanism) will be studied using circular dichroism and/or a new electrophoretic technique. Again, the influence of histone modification on the rate will be studied. There is evidence that stability of nucleosomes and their displacement on DNA may be of major importance in such processes as DNA replication, repair and transcription. Therefore, a quantitative analysis of DNA-histone interactions may be vital to a full comprehension of these processes on eukaryots.