High-complexity of DNA double-strand breaks is key for alternative end-joining choice

作者：Zhiyang Hou, Tianxiang Yu, Qiyi Yi, Yan Du, Libin Zhou, Ye Zhao, Yuejin Wu, Lijun Wu, Ting Wang, Po Bian · 发表于：Communications Biology · 年份：2024 · DOI：10.1038/s42003-024-06640-5 · 被引用次数：15 · 研究领域：DNA Repair Mechanisms、CRISPR and Genetic Engineering、Carcinogens and Genotoxicity Assessment

The repair of DNA double-strand breaks (DSBs) through alternative non-homologous end-joining (alt-NHEJ) pathway significantly contributes to genetic instability. However, the mechanism governing alt-NHEJ pathway choice, particularly its association with DSB complexity, remains elusive due to the absence of a suitable reporter system. In this study, we established a unique Escherichia coli reporter system for detecting complex DSB-initiated alternative end-joining (A-EJ), an alt-NHEJ-like pathway. By utilizing various types of ionizing radiation to generate DSBs with varying degrees of complexity, we discovered that high complexity of DSBs might be a determinant for A-EJ choice. To facilitate efficient repair of high-complexity DSBs, A-EJ employs distinct molecular patterns such as longer micro-homologous junctions and non-templated nucleotide addition. Furthermore, the A-EJ choice is modulated by the degree of homology near DSB loci, competing with homologous recombination machinery. These findings further enhance the understanding of A-EJ/alt-NHEJ pathway choice.