Telomere Biology Laboratory, Cancer Research UK, London Research Institute, London WC2A 3PX, United Kingdom.
Annu Rev Genet. 2010;44:243-69. doi: 10.1146/annurev-genet-102108-134841.
What really defines a telomere? Telomere literally is an amalgamation of the Greek words "telos," meaning end, and "mer," meaning part. In practice, it refers to the extremities of linear chromosomes. The defining functions of chromosome extremities can be summarized in two main categories. First, chromosome ends trick the cell into not identifying them as damage-induced double-strand DNA breaks (DSBs). An internal DSB immediately triggers cell-cycle arrest and is repaired to ensure that genome integrity remains undisturbed. Chromosome ends disguise themselves using assorted strategies, tailored to evade specific cellular responses. The second defining function of chromosome extremities involves self-preservation. Due to the inherent limitations of the canonical replication machinery, chromosomes gradually lose terminal DNA with successive rounds of replication. Telomeres have evolved tactics to circumvent this loss and to preserve themselves. This review focuses on highlights of telomeric strategies surrounding these two primary tasks, and finishes by discussing evidence that the full telomeric functional repertoire has yet to be defined.
端粒到底是什么？从字面上看，端粒是由希腊语“telos”（意为末端）和“mer”（意为部分）组合而成的。实际上，它指的是线性染色体的末端。染色体末端的定义功能可以概括为两大类。首先，染色体末端会欺骗细胞，使其无法将其识别为损伤诱导的双链 DNA 断裂（DSB）。内部 DSB 会立即触发细胞周期停滞，并进行修复，以确保基因组完整性不受干扰。染色体末端使用各种策略来伪装自己，以逃避特定的细胞反应。染色体末端的第二个定义功能是自我保护。由于经典复制机制的固有局限性，染色体在经过多次复制后会逐渐丢失末端 DNA。端粒已经进化出了一些策略来规避这种丢失，并保护自身。这篇综述重点介绍了端粒在这两个主要任务周围的策略，并讨论了证据表明，完整的端粒功能尚未被定义。
