Chromatin reconstitution on small DNA rings. V. DNA thermal flexibility of single nucleosomes.
Chromatin reconstitution on small DNA rings. V. DNA thermal flexibility of single nucleosomes.
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小 DNA 环上的染色质重建。
DOI：
10.1016/0022-2836(92)90821-z
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发表时间：
1992
影响因子：
5.6
通讯作者：
A. Prunell
中科院分区：
文献类型：
--
作者：
A. Hamiche;A. Prunell
相对于裸微环，测量了用单个核小体重构的DNA微环的热柔性。测量使用了一种基于这些分子的电泳特性的新方法，这些分子的流动性强烈依赖于DNA扭曲，无论是整个微环，当裸露时，还是整个核小体环，当重组时。实验如下所述。DNA长度首先增加一个碱基对（bp），并记录由改变的DNA扭曲引起的迁移率的相关变化。第二，提高凝胶温度，从而恢复先前的流动性。在这些条件下，由于温度变化而导致的热柔性DNA的解旋正好补偿了由一个bp添加引起的DNA平均扭曲数的增加。然后将相对热柔性计算为分别针对裸DNA和重构DNA测量的温度增加之间的比率。该数字0.69（±0.07）用于推导与组蛋白相互作用的DNA长度109（±25）bp。这样的长度是在很好的协议与平均值115 bp，我们以前获得的分布之间的角度在入口和出口的类似的核小体从高分辨率电子显微镜测量的DNA。这种一致性进一步加强了我们先前的结论，即具有1.3（109/83）至1.4（115/83）圈超螺旋DNA的微环重构核小体在环处于其最可能构型时没有显示出进入和退出DNA的交叉，因此，这些核小体在拓扑学上表现为“单圈”颗粒。目前的数据也在50至100 bp的热刚性DNA每个核小体，由其他人获得的酵母质粒染色质的值的范围内，这表明“单圈”颗粒的概念可以扩展到这种特定的情况下，天然存在的H1-无染色质。然而，这些数据与重建的无H1微型染色体的热测量得出的230 bp数字有很大不同。有人提出，核小体相互作用发生在这个染色质，而不是在酵母染色质，可能是部分负责的差异。
The thermal flexibility of DNA minicircles reconstituted with single nucleosomes was measured relative to the naked minicircles. The measurement used a new method based on the electrophoretic properties of these molecules, whose mobility strongly depended on the DNA writhe, either of the whole minicircle, when naked, or of the extranucleosomal loop, when reconstituted. The experiment was as follows. The DNA length was first increased by one base-pair (bp), and the correlative shift in mobility resulting from the altered DNA writhe was recorded. Second, the gel temperature was increased so that the former mobility was restored. Under these conditions, the untwisting of the thermally flexible DNA due to the temperature shift exactly compensates for the increase in the DNA mean twist number resulting from the one bp addition. The relative thermal flexibility was then calculated as the ratio between the increases in temperature measured for the naked and the reconstituted DNAs, respectively. The figure, 0.69 (±0.07), was used to derive the length of DNA in interaction with the histones, 109 (±25) bp. Such length was in good agreement with the mean value of 115 bp we have previously obtained from the distribution of the angles between DNAs at the entrance and exit of similar nucleosomes measured from high resolution electron microscopy. This consistence further reinforces our previous conclusion that minicircle-reconstituted nucleosomes, with 1.3(109/83) to 1.4(115/83) turns of superhelical DNA, show no crossing of entering and exiting DNAs when the loop is in its most probable configuration, and therefore, that these nucleosomes behave topologically as “single-turn” particles. The present data are also within the range of values, 50 to 100 bp of thermally rigid DNA per nucleosome, obtained by others for yeast plasmid chromatin, suggesting that the “single-turn” particle notion may be extended to this particular case of naturally-occurring H1-free chromatin. However, these data are quite different from the 230 bp figure derived from thermal measurements of reconstituted H1-free minichromosomes. It is proposed that nucleosome interactions occurring in this chromatin, but not in yeast chromatin, may be partly responsible for the discrepancy.
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DOI：
10.1073/pnas.84.19.6644
发表时间：
1987-10-01
影响因子：
11.1
作者：
GALE, JM;NISSEN, KA;SMERDON, MJ
通讯作者：
SMERDON, MJ
影响因子：
5.6
作者：
DREW, HR;TRAVERS, AA
通讯作者：
TRAVERS, AA
低离子强度下核小体结构的中子散射研究。
影响因子：
2.9
作者：
Uberbacher,EC;Ramakrishnan,V;Olins,DE;Bunick,GJ
通讯作者：
Bunick,GJ
胰蛋白酶化和组蛋白 H5 添加对重建微型染色体中 DNA 扭曲和拓扑的影响。
影响因子：
14.9
作者：
Morse,RH;Cantor,CR
通讯作者：
Cantor,CR
影响因子：
5.6
作者：
HOROWITZ, DS;WANG, JC
通讯作者：
WANG, JC