Rubinstein Linda, Ungar Lior, Harari Yaniv, Babin Vera, Ben-Aroya Shay, Merenyi Gabor, Marjavaara Lisette, Chabes Andrei, Kupiec Martin
Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv 69978, Israel.
Faculty of Life Sciences Bar-Ilan University, Ramat-Gan, Israel.
Nucleic Acids Res. 2014 Jun;42(10):6314-25. doi: 10.1093/nar/gku267. Epub 2014 Apr 11.
Genome-wide systematic screens in yeast have uncovered a large gene network (the telomere length maintenance network or TLM), encompassing more than 400 genes, which acts coordinatively to maintain telomere length. Identifying the genes was an important first stage; the next challenge is to decipher their mechanism of action and to organize then into functional groups or pathways. Here we present a new telomere-length measuring program, TelQuant, and a novel assay, telomere length kinetics assay, and use them to organize tlm mutants into functional classes. Our results show that a mutant defective for the relatively unknown MET7 gene has the same telomeric kinetics as mutants defective for the ribonucleotide reductase subunit Rnr1, in charge of the limiting step in dNTP synthesis, or for the Ku heterodimer, a well-established telomere complex. We confirm the epistatic relationship between the mutants and show that physical interactions exist between Rnr1 and Met7. We also show that Met7 and the Ku heterodimer affect dNTP formation, and play a role in non-homologous end joining. Thus, our telomere kinetics assay uncovers new functional groups, as well as complex genetic interactions between tlm mutants.
在酵母中进行的全基因组系统筛选发现了一个大型基因网络（端粒长度维持网络或TLM），该网络包含400多个基因，它们协同作用以维持端粒长度。识别这些基因是重要的第一步；接下来的挑战是破译它们的作用机制并将它们组织成功能组或途径。在这里，我们展示了一个新的端粒长度测量程序TelQuant和一种新的检测方法——端粒长度动力学检测，并使用它们将tlm突变体组织成功能类别。我们的结果表明，一个相对未知的MET7基因缺陷型突变体与核糖核苷酸还原酶亚基Rnr1缺陷型突变体具有相同的端粒动力学，Rnr1负责dNTP合成的限速步骤，或者与Ku异二聚体（一种成熟的端粒复合体）缺陷型突变体具有相同的端粒动力学。我们证实了这些突变体之间的上位关系，并表明Rnr1和Met7之间存在物理相互作用。我们还表明，Met7和Ku异二聚体影响dNTP的形成，并在非同源末端连接中发挥作用。因此，我们的端粒动力学检测揭示了新的功能组以及tlm突变体之间复杂的遗传相互作用。
