In eukaryotic cells, repair of DNA double-strand breaks (DSBs) by the nonhomologous end-joining (NHEJ) pathway is critical for genomic stability. A functionally homologous repair apparatus, composed of Ku and a multifunctional DNA ligase (LigD), has recently been identified in many prokaryotes. Eukaryotic organisms employ a large number of factors to repair breaks by NHEJ. In contrast, the bacterial NHEJ complex is a two-component system that, despite its relative simplicity, possesses all of the break-recognition, end-processing, and ligation activities required to facilitate the complex task of DSB repair. Here, we review recent discoveries on the structure and function of the bacterial NHEJ repair apparatus. In particular, we discuss the evolutionary origins of this DSB repair pathway, how the diverse activities within the prokaryotic end-joining complex cooperate to facilitate DSB repair, the physiological roles of bacterial NHEJ, and finally, the essential function of NHEJ in the life cycle of mycobacteriophage.

中文翻译：

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细菌中的非同源末端连接：微生物视角。

在真核细胞中，通过非同源末端连接 (NHEJ) 途径修复 DNA 双链断裂 (DSB) 对于基因组稳定性至关重要。最近在许多原核生物中发现了一种功能同源的修复装置，由 Ku 和多功能 DNA 连接酶 (LigD) 组成。真核生物利用大量因子来修复 NHEJ 的断裂。相比之下，细菌 NHEJ 复合物是一个双组分系统，尽管它相对简单，但它拥有促进 DSB 修复复杂任务所需的所有断裂识别、末端处理和连接活动。在这里，我们回顾了最近关于细菌 NHEJ 修复装置的结构和功能的发现。特别是，我们讨论了这种 DSB 修复途径的进化起源，