Rad5 dysregulation drives hyperactive recombination at replication forks resulting in cisplatin sensitivity and genome instability

• Published in: Nucleic acids research Vol. 47; no. 17; pp. 9144 - 9159
• Main Authors: Bryant, Eric E, Šunjevarić, Ivana, Berchowitz, Luke, Rothstein, Rodney, Reid, Robert J D
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 26.09.2019
• Subjects: Cisplatin - pharmacology; Crossing Over, Genetic - genetics; DNA Damage - drug effects; DNA Helicases - genetics; DNA Repair - genetics; DNA Replication - drug effects; DNA Replication - genetics; DNA-Binding Proteins - genetics; Gene Expression Regulation, Fungal - drug effects; Genome Integrity, Repair and; Genomic Instability - genetics; Humans; Neoplasms - genetics; Recombination, Genetic - genetics; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae Proteins - genetics; Transcription Factors - genetics
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/gkz631

The postreplication repair gene, HLTF, is often amplified and overexpressed in cancer. Here we model HLTF dysregulation through the functionally conserved Saccharomyces cerevisiae ortholog, RAD5. Genetic interaction profiling and landscape enrichment analysis of RAD5 overexpression (RAD5OE) reveals requirements for genes involved in recombination, crossover resolution, and DNA replication. While RAD5OE and rad5Δ both cause cisplatin sensitivity and share many genetic interactions, RAD5OE specifically requires crossover resolving genes and drives recombination in a region of repetitive DNA. Remarkably, RAD5OE induced recombination does not require other post-replication repair pathway members, or the PCNA modification sites involved in regulation of this pathway. Instead, the RAD5OE phenotype depends on a conserved domain necessary for binding 3' DNA ends. Analysis of DNA replication intermediates supports a model in which dysregulated Rad5 causes aberrant template switching at replication forks. The direct effect of Rad5 on replication forks in vivo, increased recombination, and cisplatin sensitivity predicts similar consequences for dysregulated HLTF in cancer.