Molecular Biological Studies on Telomere Structure, Function and Maintenance

利用分裂酵母、爪蟾卵提取物和哺乳动物培养细胞对端粒结构和功能进行了研究。选择这些模式生物是因为它们分别高度适合于遗传、生化和细胞生物学分析。在裂变酵母中发现了新的端粒组分spRap1、SpRif1、Ccq1、Poz1。在爪蟾卵提取物中发现端粒dna结合蛋白TRF1以细胞周期依赖的方式与染色质结合并分离。利用SV40复制系统，分析了末端复制问题的分子机理。发现端粒DNA本身和端粒染色质都不是进行复制反应的良好底物。利用含有温度敏感DNA聚合酶a的小鼠细胞，研究人员发现端粒是最易受复制压力影响的基因组区域之一。研究发现，表观遗传和遗传机制共同维持端粒的功能。这些研究揭示了端粒结构和功能的新方面，这将扩展我们对衰老和癌细胞中明显随机的染色体行为的理解。此外，通过对不同模式生物进行并行研究，以跨物种互动的方式促进研究的“元生物学”是非常高效和富有成效的。

Telomere structures and functions were studied using fission yeast, Xenopus egg extracts and mammalian cultured cells. These model organisms were chosen because they are highly amenable to genetic, biochemical and cell biological analyses, respectively.1. Novel telomeric components, spRap1,SpRif1,Ccq1,Poz1,were identified in fission yeast.2. Telomere DNA-binding protein TRF1 was found to associate with and dissociate from chromatin in a cell-cycle-dependent manner in Xenopus egg extracts.3. Using the SV40 replication system, the molecular mechanism of the end replication problem was analyzed. It was found that telomeric DNA by itself as well as telomere chromatin is not a good substrate for replication reactions.4. Using murine cells harboring temperature-sensitive DNA polymerase a, it was found that the telomere comprises one of the most vulnerable genomic regions to replication stresses.5. It was found that epigenetic as well as genetic mechanisms cooperate to maintain the telomere functions.These studies revealed new aspects of telomere structures and functions, which will extend our understanding of apparently stochastic chromosomal behaviors in aging and cancer cells. Moreover, it became evident that "meta-biology", studying different model organisms in parallel to promote the research in an cross-species interactive manner is highly efficient and productive.