染色体外DNA生物合成与基因组DNA修复的不同途径。
Disparate pathways for extrachromosomal DNA biogenesis and genomic DNA repair.
作者信息
Rose John C, Wong Ivy Tsz-Lo, Daniel Bence, Jones Matthew G, Yost Kathryn E, Hung King L, Curtis Ellis J, Mischel Paul S, Chang Howard Y
机构信息
Center for Personal Dynamic Regulomes, Stanford University, Stanford, CA, USA.
Sarafan ChEM-H, Stanford University, Stanford, CA, USA.
出版信息
bioRxiv. 2023 Oct 23:2023.10.22.563489. doi: 10.1101/2023.10.22.563489.
Oncogene amplification on extrachromosomal DNA (ecDNA) is a pervasive driver event in cancer, yet our understanding of how ecDNA forms is limited. Here, we couple a CRISPR-based method for induction of ecDNA with extensive characterization of newly formed ecDNA to examine ecDNA biogenesis. We find that DNA circularization is efficient, irrespective of 3D genome context, with formation of a 1 Mb and 1.8 Mb ecDNA both reaching 15%. We show non-homologous end joining and microhomology mediated end joining both contribute to ecDNA formation, while inhibition of DNA-PKcs and ATM have opposing impacts on ecDNA formation. EcDNA and the corresponding chromosomal excision scar form at significantly different rates and respond differently to DNA-PKcs and ATM inhibition. Taken together, our results support a model of ecDNA formation in which double strand break ends dissociate from their legitimate ligation partners prior to joining of illegitimate ends to form the ecDNA and excision scar.
染色体外DNA（ecDNA）上的癌基因扩增是癌症中普遍存在的驱动事件，但我们对ecDNA如何形成的了解有限。在这里，我们将基于CRISPR的ecDNA诱导方法与新形成的ecDNA的广泛表征相结合，以研究ecDNA的生物发生。我们发现，无论3D基因组背景如何，DNA环化都是有效的，1 Mb和1.8 Mb ecDNA的形成率均达到15%。我们表明，非同源末端连接和微同源性介导的末端连接都有助于ecDNA的形成，而抑制DNA-PKcs和ATM对ecDNA的形成有相反的影响。EcDNA和相应的染色体切除疤痕以显著不同的速率形成，并且对DNA-PKcs和ATM抑制的反应也不同。综上所述，我们的结果支持一种ecDNA形成模型，即双链断裂末端在与非法末端连接以形成ecDNA和切除疤痕之前，先与其合法的连接伙伴解离。
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