RESUMEN
DNA base damage is a major source of oncogenic mutations1. Such damage can produce strand-phased mutation patterns and multiallelic variation through the process of lesion segregation2. Here we exploited these properties to reveal how strand-asymmetric processes, such as replication and transcription, shape DNA damage and repair. Despite distinct mechanisms of leading and lagging strand replication3,4, we observe identical fidelity and damage tolerance for both strands. For small alkylation adducts of DNA, our results support a model in which the same translesion polymerase is recruited on-the-fly to both replication strands, starkly contrasting the strand asymmetric tolerance of bulky UV-induced adducts5. The accumulation of multiple distinct mutations at the site of persistent lesions provides the means to quantify the relative efficiency of repair processes genome wide and at single-base resolution. At multiple scales, we show DNA damage-induced mutations are largely shaped by the influence of DNA accessibility on repair efficiency, rather than gradients of DNA damage. Finally, we reveal specific genomic conditions that can actively drive oncogenic mutagenesis by corrupting the fidelity of nucleotide excision repair. These results provide insight into how strand-asymmetric mechanisms underlie the formation, tolerance and repair of DNA damage, thereby shaping cancer genome evolution.
Asunto(s)
Daño del ADN , Reparación del ADN , ADN Polimerasa Dirigida por ADN , ADN , Mutagénesis , Mutación , Animales , Humanos , Ratones , Alquilación/efectos de la radiación , Línea Celular , ADN/química , ADN/genética , ADN/metabolismo , ADN/efectos de la radiación , Aductos de ADN/química , Aductos de ADN/genética , Aductos de ADN/metabolismo , Aductos de ADN/efectos de la radiación , Daño del ADN/genética , Daño del ADN/efectos de la radiación , Reparación del ADN/genética , Reparación del ADN/fisiología , Replicación del ADN , ADN Polimerasa Dirigida por ADN/metabolismo , Mutagénesis/genética , Mutagénesis/efectos de la radiación , Mutación/genética , Mutación/efectos de la radiación , Neoplasias/genética , Transcripción Genética , Rayos Ultravioleta/efectos adversosRESUMEN
Copy number alterations (CNAs) are among the most important genetic events in cancer, but their detection from sequencing data is challenging because of unknown sample purity, tumor ploidy, and general intra-tumor heterogeneity. Here, we present CNAqc, an evolution-inspired method to perform the computational validation of clonal and subclonal CNAs detected from bulk DNA sequencing. CNAqc is validated using single-cell data and simulations, is applied to over 4000 TCGA and PCAWG samples, and is incorporated into the validation process for the clinically accredited bioinformatics pipeline at Genomics England. CNAqc is designed to support automated quality control procedures for tumor somatic data validation.