Mutational signatures reveal the role of RAD52 in p53-independent p21-driven genomic instability

Research output: Contribution to journalJournal articleResearchpeer-review

Panagiotis Galanos, George Pappas, Alexander Polyzos, Athanassios Kotsinas, Ioanna Svolaki, Nickolaos N Giakoumakis, Christina Glytsou, Ioannis S Pateras, Umakanta Swain, Vassilis L Souliotis, Alexandros G Georgakilas, Nicholas Geacintov, Luca Scorrano, Claudia Lukas, Jiri Lukas, Zvi Livneh, Zoi Lygerou, Dipanjan Chowdhury, Claus Storgaard Sørensen, Jiri Bartek & 1 others Vassilis G Gorgoulis

BACKGROUND: Genomic instability promotes evolution and heterogeneity of tumors. Unraveling its mechanistic basis is essential for the design of appropriate therapeutic strategies. In a previous study, we reported an unexpected oncogenic property of p21WAF1/Cip1, showing that its chronic expression in a p53-deficient environment causes genomic instability by deregulation of the replication licensing machinery.

RESULTS: We now demonstrate that p21WAF1/Cip1can further fuel genomic instability by suppressing the repair capacity of low- and high-fidelity pathways that deal with nucleotide abnormalities. Consequently, fewer single nucleotide substitutions (SNSs) occur, while formation of highly deleterious DNA double-strand breaks (DSBs) is enhanced, crafting a characteristic mutational signature landscape. Guided by the mutational signatures formed, we find that the DSBs are repaired by Rad52-dependent break-induced replication (BIR) and single-strand annealing (SSA) repair pathways. Conversely, the error-free synthesis-dependent strand annealing (SDSA) repair route is deficient. Surprisingly, Rad52 is activated transcriptionally in an E2F1-dependent manner, rather than post-translationally as is common for DNA repair factor activation.

CONCLUSIONS: Our results signify the importance of mutational signatures as guides to disclose the repair history leading to genomic instability. We unveil how chronic p21WAF1/Cip1expression rewires the repair process and identifies Rad52 as a source of genomic instability and a candidate therapeutic target.

Original languageEnglish
Article number37
JournalGenome Biology (Online Edition)
Pages (from-to)1-18
Publication statusPublished - 2018

    Research areas

  • Break-induced replication (BIR), Genomic instability, P21, Rad52, Single nucleotide substitution (SNS), Single strand annealing (SSA), Translesion DNA synthesis (TLS)

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