Dynamic Organization of Chromatin Replication

维持DNA的遗传信息是染色体区域和靶向特征核结构域的功能蛋白之间的动态相互作用。我们研究染色体DNA和复制机制之间的相互作用，通过高分辨率延时显微镜活哺乳动物细胞的复制焦点为目标。本更新申请描述了项目前1.5年期间取得的成果。我们可以表明，在S期的复制焦点的变化模式，第一次不是由于通过核焦点的运动。单个复制灶在特定的核位点组装，在给定的时间内保持该位置，并在完成局部DNA复制后解体。不同焦点的组装和拆卸异步发生。复制焦点和复制的DNA在给定的核位置相对于彼此移动。我们目前正在测试这些运动是否是由于DNA在复制工厂中的旋转。结果还表明，复制灶含有能够复制几个单独的亚染色体灶的超结构。未来的实验将揭示这是否是由于一个定义的空间/时间轨道的亚染色体病灶的个别复制病灶的识别。

Maintaining the genetic information of the DNA is a dynamic interplay between chromosome territories and functional proteins targeted to characteristic nuclear domains. We investigate the interplay between chromosomal DNA and the replication machinery targeted to replication foci by high resolution time-lapse microscopy of living mammalian cells. This renewal application describes the results obtained during the first 1.5 years of the project. We could show for the first time that the changing patterns of replication foci during S-phase are not due to movements of foci through the nucleus. Individual replication foci assemble at a particular nuclear site, keep this position for a given period, and disassemble after finishing local DNA replication. Assembly and disassembly of different foci occurs asynchronously. Replication foci and replicated DNA move relatively to each other at given nuclear positions. We are currently testing whether these movements are due to a reeling of DNA through the replication factory. The results also suggest that replication foci contain hyperstructures able to replicate several individual subchromosomal foci. Future experiments will reveal whether this is due to a recognition of a defined spatio-/temporal track of subchromosomal foci by individual replication foci.