Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom.
Institute of Cancer and Genetics, School of Medicine, Cardiff University, CF14 4XN, United Kingdom.
G3 (Bethesda). 2017 Jul 5;7(7):2375-2389. doi: 10.1534/g3.117.042283.
Functional telomeres are critically important to eukaryotic genetic stability. Scores of proteins and pathways are known to affect telomere function. Here, we report a series of related genome-wide genetic interaction screens performed on budding yeast cells with acute or chronic telomere defects. Genetic interactions were examined in cells defective in Cdc13 and Stn1, affecting two components of CST, a single stranded DNA (ssDNA) binding complex that binds telomeric DNA. For comparison, genetic interactions were also examined in cells with defects in Rfa3, affecting the major ssDNA binding protein, RPA, which has overlapping functions with CST at telomeres. In more complex experiments, genetic interactions were measured in cells lacking or , affecting different aspects of the DNA damage response, and containing a induced telomere defect. Comparing fitness profiles across these data sets helps build a picture of the specific responses to different types of dysfunctional telomeres. The experiments show that each context reveals different genetic interactions, consistent with the idea that each genetic defect causes distinct molecular defects. To help others engage with the large volumes of data, the data are made available via two interactive web-based tools: Profilyzer and DIXY. One particularly striking genetic interaction observed was that the mutation improved fitness of cells more than other checkpoint mutations (, , , and ), whereas, in cells, the effects of all checkpoint mutations were similar. We show that this can be explained by Chk1 stimulating resection-a new function for Chk1 in the eukaryotic DNA damage response network.
功能端粒对真核生物遗传稳定性至关重要。已知有大量的蛋白质和途径影响端粒功能。在这里，我们报告了一系列在具有急性或慢性端粒缺陷的酵母细胞中进行的相关全基因组遗传相互作用筛选。在影响 CST（一种结合端粒 DNA 的单链 DNA（ssDNA）结合复合物的两个组件的 Cdc13 和 Stn1 缺陷细胞中检查了遗传相互作用）的细胞中进行了比较，CST 是一种结合端粒 DNA 的单链 DNA（ssDNA）结合复合物。为了进行比较，还在影响主要 ssDNA 结合蛋白 RPA（其在端粒处与 CST 具有重叠功能）的 Rfa3 缺陷细胞中检查了遗传相互作用。在更复杂的实验中，在缺乏 或 ，影响 DNA 损伤反应的不同方面且包含 诱导的端粒缺陷的细胞中测量了遗传相互作用。比较这些数据集的适应性曲线有助于构建对不同类型功能失调端粒的特定反应的图像。实验表明，每种情况都揭示了不同的遗传相互作用，这与每个遗传缺陷导致不同的分子缺陷的想法一致。为了帮助其他人处理大量数据，通过两个交互式基于网络的工具提供了数据：Profilyzer 和 DIXY。观察到的一个特别引人注目的遗传相互作用是 突变比其他检查点突变（ 、 、 和 ）更能改善 细胞的适应性，而在 细胞中，所有检查点突变的效果相似。我们表明，这可以通过 Chk1 刺激切除来解释-在真核生物 DNA 损伤反应网络中 Chk1 的新功能。
