Ten1p promotes the telomeric DNA-binding activity of Cdc13p： implication for its function in telomere length regulation

在 Saccharomyces cerevisiae，必要基因 CDC13 编码 telomeric 遗传上并且身体上与 Stn1p 和 Ten1p 交往的搁浅单人赛的 DNA 有约束力的蛋白质，并且为 telomere 结束保护和 telomere 长度控制被要求。Ten1 由参予 telomere 长度规定和染色体结束保护的分子的机制留下逃犯。在这个工作，我们用净化的 recombinant Cdc13p 和 Ten1p 在胶化过滤分析观察了 Cdc13p 和 Ten1p 的一个弱相互作用。Ten1p 本身展出一项弱 DNA 有约束力的活动，但是提高 telomeric TG1 鈥吗？Cdc13p 的 DNA 有约束力的能力。Cdc13p 是有 Ten1p 的 co-immunoprecipitated。在变异的 ten1-55 或 ten1-66 房间，在 Ten1p 和 Cdc13p 之间的损害相互作用与 telomeric DNA 导致长得多的 telomeres，以及 Cdc13p 的一个减少的协会。一致地， Ten1-55 和 Ten1-66 异种蛋白质没能刺激 telomeric 在 vitro 的 Cdc13p 的 DNA 有约束力的活动。这些结果建议 Ten1p 提高 telomeric Cdc13p 到的 DNA 有约束力的活动否定地调整 telomere 长度。

In Saccharomyces cerevisiae, the essential gene CDC13 encodes a telomeric single-stranded DNA-binding protein that interacts with Stnlp and Tenlp genetically and physically, and is required for telomere end protection and telomere length control. The molecular mechanism by which Tenl participates in telomere length regulation and chromosome end protection remains elusive. In this work, we observed a weak interaction of Cdc13p and Tenlp in a gelfiltration analysis using purified recombinant Cdc13p and Tenlp. Tenlp itself exhibits a weak DNA-binding activity, but enhances the telomeric TG1-3 DNA-binding ability of Cdc13p. Cdc13p is communoprecipitated with Tenlp. In the mutant ten1-55 or ten1-66 cells, the impaired interaction between Tenlp and Cdc13p results in much longer telomeres, as well as a decreased association of Cdc13p with telomeric DNA. Consistently, the Ten1-55 and Ten1-66 mutant proteins fail to stimulate the telomeric DNA-binding activity of Cdc13p in vitro. These results suggest that Tenlp enhances the telomeric DNA-binding activity of Cdc13p to negatively regulate telomere length.