Nanbu Tomoko, Nguyễn Luân C, Habib Ahmed G K, Hirata Naoya, Ukimori Shinobu, Tanaka Daiki, Masuda Kenta, Takahashi Katsunori, Yukawa Masashi, Tsuchiya Eiko, Ueno Masaru
Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8530, Japan.
Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8530, Japan; Research Center for the Mathematics on Chromatin Live Dynamics, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8530, Japan.
PLoS One. 2015 Oct 14;10(10):e0140456. doi: 10.1371/journal.pone.0140456. eCollection 2015.
The uncapping of telomeres induces a DNA damage response. In Schizosaccharomyces pombe, deletion of pot1+ causes telomere uncapping and rapid telomere resection, resulting in chromosome fusion. Using the nmt-pot1-aid strain, we previously reported that Pot1 shut-off causes telomere loss and chromosome fusion in S. pombe. However, the factors responsible for the resection of uncapped telomeres remain unknown. In this study, we investigated these factors and found that concomitant deletion of rqh1+ and exo1+ alleviated the loss of telomeres following Pot1 shut-off, suggesting that Rqh1 and Exo1 are redundantly involved in the resection of uncapped telomeres. We also investigated the role of Rqh1 helicase activity and found it to be essential for the resection of uncapped telomeres. Moreover, we found that Dna2 and Exo1 function redundantly in the resection of uncapped telomeres. Taken together, these results suggest that Exo1 and Rqh1-Dna2 redundantly contribute to the resection of uncapped telomeres. Therefore, our results demonstrate that nmt-pot1-aid is an important model strain to study the role of helicases and nucleases in the resection of uncapped telomeres and to improve our understanding of DNA double-strand break repair.
端粒去帽会引发DNA损伤反应。在粟酒裂殖酵母中，缺失pot1+会导致端粒去帽和端粒快速切除，从而导致染色体融合。我们之前使用nmt-pot1-aid菌株报道过，Pot1的关闭会导致粟酒裂殖酵母中的端粒丢失和染色体融合。然而，负责切除去帽端粒的因素仍然未知。在本研究中，我们对这些因素进行了研究，发现同时缺失rqh1+和exo1+可缓解Pot1关闭后端粒的丢失，这表明Rqh1和Exo1在去帽端粒的切除中存在冗余作用。我们还研究了Rqh1解旋酶活性的作用，发现它对于去帽端粒的切除至关重要。此外，我们发现Dna2和Exo1在去帽端粒的切除中也存在冗余功能。综上所述，这些结果表明Exo1和Rqh1-Dna2在去帽端粒的切除中发挥了冗余作用。因此，我们的结果表明nmt-pot1-aid是研究解旋酶和核酸酶在去帽端粒切除中的作用以及增进我们对DNA双链断裂修复理解的重要模型菌株。
