Ghosh Santanu Kumar, Hajra Sujata, Paek Andrew, Jayaram Makkuni
Section of Molecular Genetics and Microbiology, University of Texas at Austin, Austin, Texas 78712-0612, USA.
Annu Rev Biochem. 2006;75:211-41. doi: 10.1146/annurev.biochem.75.101304.124037.
The fundamental problems in duplicating and transmitting genetic information posed by the geometric and topological features of DNA, combined with its large size, are qualitatively similar for prokaryotic and eukaryotic chromosomes. The evolutionary solutions to these problems reveal common themes. However, depending on differences in their organization, ploidy, and copy number, chromosomes and plasmids display distinct segregation strategies as well. In bacteria, chromosome duplication, likely mediated by a stationary replication factory, is accompanied by rapid, directed migration of the daughter duplexes with assistance from DNA-compacting and perhaps translocating proteins. The segregation of unit-copy or low-copy bacterial plasmids is also regulated spatially and temporally by their respective partitioning systems. Eukaryotic chromosomes utilize variations of a basic pairing and unpairing mechanism for faithful segregation during mitosis and meiosis. Rather surprisingly, the yeast plasmid 2-micron circle also resorts to a similar scheme for equal partitioning during mitosis.
由DNA的几何和拓扑特征以及其较大尺寸所带来的复制和传递遗传信息的基本问题，对于原核生物和真核生物染色体而言在性质上是相似的。针对这些问题的进化解决方案揭示了共同的主题。然而，由于染色体和质粒在组织、倍性和拷贝数上存在差异，它们也展现出不同的分离策略。在细菌中，染色体复制可能由一个固定的复制工厂介导，伴随着子代双链在DNA压缩蛋白以及可能的转运蛋白的协助下进行快速、定向的迁移。单拷贝或低拷贝细菌质粒的分离也通过各自的分配系统在空间和时间上受到调控。真核生物染色体在有丝分裂和减数分裂期间利用一种基本的配对和解对机制的变体来实现准确分离。相当令人惊讶的是，酵母质粒2-微米环在有丝分裂期间也采用类似的方案进行均等分配。
