Weinreich Michael, Palacios DeBeer Madeleine A, Fox Catherine A
Laboratory of Chromosome Replication, Van Andel Research Institute, 333 Bostwick Ave NE, Grand Rapids, MI 49503, USA.
Biochim Biophys Acta. 2004 Mar 15;1677(1-3):142-57. doi: 10.1016/j.bbaexp.2003.11.015.
DNA replication initiates at chromosomal positions called replication origins. This review will focus on the activity, regulation and roles of replication origins in Saccharomyces cerevisiae. All eukaryotic cells, including S. cerevisiae, depend on the initiation (activity) of hundreds of replication origins during a single cell cycle for the duplication of their genomes. However, not all origins are identical. For example, there is a temporal order to origin activation with some origins firing early during the S-phase and some origins firing later. Recent studies provide evidence that posttranslational chromatin modifications, heterochromatin-binding proteins and nucleosome positioning can control the efficiency and/or timing of chromosomal origin activity in yeast. Many more origins exist than are necessary for efficient replication. The availability of excess replication origins leaves individual origins free to evolve distinct forms of regulation and/or roles in chromosomes beyond their fundamental role in DNA synthesis. We propose that some origins have acquired roles in controlling chromatin structure and/or gene expression. These roles are not linked obligatorily to replication origin activity per se, but instead exploit multi-subunit replication proteins with the potential to form context-dependent protein-protein interactions.
DNA复制起始于被称为复制起点的染色体位置。本综述将聚焦于酿酒酵母中复制起点的活性、调控及其作用。包括酿酒酵母在内的所有真核细胞，在单个细胞周期中都依赖数百个复制起点的起始（活性）来复制其基因组。然而，并非所有起点都是相同的。例如，起点激活存在时间顺序，一些起点在S期早期启动，一些起点则在后期启动。最近的研究表明，翻译后染色质修饰、异染色质结合蛋白和核小体定位可控制酵母中染色体起点活性的效率和/或时间。存在的复制起点数量多于高效复制所需的数量。多余复制起点的存在使单个起点能够自由进化出除了其在DNA合成中的基本作用之外，在染色体中独特的调控形式和/或作用。我们提出，一些起点已在控制染色质结构和/或基因表达方面发挥作用。这些作用并非必然与复制起点活性本身相关联，而是利用具有形成依赖于上下文的蛋白质-蛋白质相互作用潜力的多亚基复制蛋白。
