Skalníková M, Kozubek S, Lukásová E, Bártová E, Jirsová P, Cafourková A, Koutná I, Kozubek M
Faculty of Informatics, Masaryk University, Botanická, Brno, Czech Republic.
Chromosome Res. 2000;8(6):487-99. doi: 10.1023/a:1009267605580.
Higher-order compartments of nuclear chromatin have been defined according to the replication timing, transcriptional activity, and information content (Ferreira et al. 1997, Sadoni et al. 1999). The results presented in this work contribute to this model of nuclear organization. Using different human blood cells, nuclear positioning of genes, centromeres, and whole chromosomes was investigated. Genes are located mostly in the interior of cell nuclei; centromeres are located near the nuclear periphery in agreement with the definition of the higher-order compartments. Genetic loci are found in specific subregions of cell nuclei which form distinct layers at defined centre-of-nucleus to locus distances. Inside these layers, the genetic loci are distributed randomly. Some chromosomes are polarized with genes located in the inner parts of the nucleus and centromere located on the nuclear periphery; polar organization was not found for some other chromosomes. The internal structure of the higher-order compartments as well as the polar and non-polar organization of chromosomes are basically conserved in different cell types and at various stages of the cell cycle. Some features of the nuclear structure are conserved even in differentiated cells and during cellular repair after irradiation, although shifted positioning of genetic loci was systematically observed during these processes.
核染色质的高阶结构域已根据复制时间、转录活性和信息含量进行了定义（费雷拉等人，1997年；萨多尼等人，1999年）。本研究中呈现的结果有助于完善这种核组织模型。利用不同的人类血细胞，研究了基因、着丝粒和整条染色体在细胞核中的定位。基因大多位于细胞核内部；着丝粒位于核周边附近，这与高阶结构域的定义相符。遗传位点存在于细胞核的特定子区域，这些子区域在从细胞核中心到位点的特定距离处形成不同的层。在这些层内部，遗传位点随机分布。一些染色体呈极化状态，基因位于核内部，着丝粒位于核周边；而其他一些染色体则未发现极化组织。高阶结构域的内部结构以及染色体的极化和非极化组织在不同细胞类型和细胞周期的各个阶段基本保持不变。即使在分化细胞以及辐射后的细胞修复过程中，核结构的一些特征也得以保留，尽管在这些过程中系统地观察到了遗传位点定位的变化。
