Molecular Mechanism on the Regulation of Telomere Structure by Checkpoint Factors

检查点因子调控端粒结构的分子机制

• 批准号: 16570007
• 负责人: MATSUURA Akira
• 金额: $ 2.37万
• 依托单位: National Institute for Longevity Sciences, National Center for Geriatrics and Gerontology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16570007/
• 关键词: telomere; checkpoint; ATM-related proteins; cell cycle; telomerase; DNA double-strand repair; クロマチン免疫沈降法; DNA末端修復; MRX複合体; クロマチン免疫沈隆法

The telomere is an essential nucleoprotein structure that protects the ends of eukaryotic linear chromosomes. The telomere DNA consists of a unique repeat that is synthesized by telomerase, which is a specialized reverse transcriptase. Due to problems with end-replication, cells that lack telomerase activity are unable to maintain the original telomere length after replication. Therefore, successive rounds of replication in telomerase-deficient cells generate unstable telomere-less chromosomes, which subsequently cause impairment of cell proliferation.The maintenance of telomeric DNA requires additional factors, at least in yeasts, including a wide range of proteins that are involved in DNA metabolism. Using the chromain immunoprecipitation assay, we showed that Tel1p and Mec1p, PIKK family proteins in Saccharomyces cerevisiae, were recruited to the telomeres at specific times in the cell cycle, in a mutually exclusive manner. Mec1p interacted with the telomeres during late S phase, and this interaction required its own kinase activity, which peaked during the S phase. Moreover, we showed that the MRX (Mre11-Rad50-Xrs2) complex, which functions in DNA double-strand break repair, was recruited to the telomeres in the late S phase, and that its loading was related to the extension of single-stranded telomere tails during this period. MRX was required for the late S phase-specific recruitment of Mec1 (ATR) to the telomeres. Mec1, in turn, contributed to the assembly of the telomerase regulators Cdc13 and Est1 at the telomere ends. Based on these results, we proposed a model for the hierarchical assembly of telomere replication proteins in the late S phase, which involves triggering by the loading of MRX onto the chromosome termini. The recruitment of DNA repair-related proteins to the telomeres at particular times in the cell cycle suggests that the normal terminus of a chromosome is recognized as a DNA double-strand break once per cell cycle.

端粒是保护真核线性染色体末端的重要核蛋白结构。端粒 DNA 由端粒酶（一种特殊的逆转录酶）合成的独特重复序列组成。由于末端复制的问题，缺乏端粒酶活性的细胞在复制后无法维持原始的端粒长度。因此，端粒酶缺陷细胞中的连续几轮复制会产生不稳定的无端粒染色体，从而导致细胞增殖受损。端粒 DNA 的维持需要额外的因素，至少在酵母中是这样，包括参与端粒酶的多种蛋白质。 DNA代谢。使用染色质免疫沉淀测定，我们发现酿酒酵母中的 PIKK 家族蛋白 Tel1p 和 Mec1p 在细胞周期的特定时间以相互排斥的方式被招募到端粒。 Mec1p 在 S 期晚期与端粒相互作用，这种相互作用需要其自身的激酶活性，该活性在 S 期达到峰值。此外，我们还发现，在DNA双链断裂修复中发挥作用的MRX（Mre11-Rad50-Xrs2）复合物在S期晚期被招募到端粒，并且其负载与单链的延伸有关。在此期间端粒尾巴。 Mec1 (ATR) 到端粒的晚期 S 期特异性募集需要 MRX。 Mec1 反过来又有助于端粒酶调节因子 Cdc13 和 Est1 在端粒末端的组装。基于这些结果，我们提出了一个模型，用于晚 S 期端粒复制蛋白的分层组装，其中涉及通过将 MRX 加载到染色体末端来触发。在细胞周期的特定时间，DNA修复相关蛋白被募集到端粒，这表明染色体的正常末端在每个细胞周期被识别为DNA双链断裂一次。

项目成果

デロメアクロマチンの動的制御とATMファミリー

脱粒染色质和 ATM 家族的动态调控

• 发表时间: 2005
• 期刊: 生化学 77
• 作者: Itakura E;et al.;松浦彰
• 通讯作者: 松浦彰

Reciprocal association of the budding yeast ATM-related proteins Tell and Mecl with telomeres in vivo

芽殖酵母 ATM 相关蛋白 Tell 和 Mecl 与体内端粒的相互关联

• 发表时间: 2004
• 期刊: Mol. Cell 14
• 作者: Takaha H;et al.
• 通讯作者: et al.

Reciprocal association of the budding yeast ATM-related proteins Tel1 and Mec1 with telomeres in vivo.

芽殖酵母 ATM 相关蛋白 Tel1 和 Mec1 与体内端粒的相互关联。

• 发表时间: 2004
• 期刊: Mol.Cell 14
• 作者: H.Takata;Y.Kanoh;N.Gunge;K.Shirahige;Akira Matsuura
• 通讯作者: Akira Matsuura

Late S phase-specific recruitment of Mre11 complex triggers hierarchical assembly of telomere replication proteins in Saccharomyces cerevisiae.

• DOI: 10.1016/j.molcel.2005.01.014
• 发表时间: 2005-02
• 期刊: Molecular cell
• 影响因子: 16
• 作者: H. Takata;Yayoi Tanaka;A. Matsuura

Late S phase-specific recruitment of Mrel1 complex triggers hierarchical assembly of telomere replication proteins in Saccharomyces cerevisiae.

Mrel1 复合物的晚期 S 期特异性募集触发了酿酒酵母中端粒复制蛋白的分层组装。

• 发表时间: 2005
• 期刊: Mol.Cell 17
• 作者: Itakura E;et al.;松浦彰;Takata H. et al.
• 通讯作者: Takata H. et al.