Hearst J E, Kauffman L, McClain W M
Department of Chemistry, University of California, Berkeley 94720-1460, USA.
Trends Genet. 1998 Jun;14(6):244-7. doi: 10.1016/s0168-9525(98)01481-4.
The interphase nucleus of the human eukaryotic cell, before DNA replication, contains 46 linear DNA molecules, each of the order of centimeters in length, in a spherical nucleus with a diameter of 3-10 microns. How does the cell avoid topological entanglements between the 92 linear DNA molecules following replication? A model of chromosome replication is introduced, based on the assumption of the existence of a physical linkage between diverging growing forks during eukaryotic chromosome replication. This basic model is shown to be sufficient for the avoidance of DNA duplex entanglements during DNA replication. The model also suggests structural characteristics of chromosomes at various points in the cell cycle and provides a possible partial mechanism for chromosome condensation at the end of replication.
在DNA复制之前，人类真核细胞的间期核在直径为3 - 10微米的球形核中包含46个线性DNA分子，每个分子长度约为几厘米。复制后，细胞如何避免92个线性DNA分子之间的拓扑缠结？基于真核染色体复制过程中发散生长叉之间存在物理连接的假设，引入了一种染色体复制模型。该基本模型被证明足以避免DNA复制过程中的DNA双链缠结。该模型还揭示了细胞周期不同阶段染色体的结构特征，并为复制结束时的染色体浓缩提供了一种可能的部分机制。
