Molecular Biological Studies on Telomere Structure, Function and Maintenance

利用分裂酵母、非洲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非常适合于遗传、生物化学和细胞生物学分析。在裂殖酵母中发现了新的端粒组分spRap1，SpRif1，Ccq1，Poz1.端粒DNA结合蛋白TRF1在非洲爪蟾卵提取物中以细胞周期依赖的方式与染色质结合和解离.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本身以及端粒染色质不是复制反应的良好底物.使用携带温度敏感性DNA聚合酶a的小鼠细胞，发现端粒包含最易受复制应激影响的基因组区域之一。这些研究揭示了端粒结构和功能的新方面，将扩展我们对衰老和癌细胞中染色体随机行为的认识。此外，“元生物学”，即平行研究不同的模式生物，以跨物种互动的方式促进研究，是非常有效和富有成效的。

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.