Genetic determinants of cellular addiction to DNA polymerase theta

• Published in: Nature communications 2019-09, Vol.10 (1), p.4286-13, Article 4286
• Main Authors: Feng, Wanjuan, Simpson, Dennis A., Carvajal-Garcia, Juan, Price, Brandon A., Kumar, Rashmi J., Mose, Lisle E., Wood, Richard D., Rashid, Naim, Purvis, Jeremy E., Parker, Joel S., Ramsden, Dale A., Gupta, Gaorav P.
• Format: Article
• Language: English
• Subjects: 13/1; 45; 45/22; 45/41; 45/47; 49; 49/23; 631/337/1427/2122; 631/337/4041/3196; 631/67/69; Addictions; Aminoquinolines - toxicity; Animals; Breast; Breast cancer; Breast Neoplasms - genetics; Cell Line; CRISPR; CRISPR-Cas Systems - genetics; Deoxyribonucleic acid; DNA; DNA Breaks, Double-Stranded; DNA damage; DNA End-Joining Repair - genetics; DNA polymerase; DNA Polymerase theta; DNA-directed DNA polymerase; DNA-Directed DNA Polymerase - genetics; DNA-Directed DNA Polymerase - metabolism; Double-strand break repair; Genes; Genetic screening; HEK293 Cells; Homologous recombination; Homology; Humanities and Social Sciences; Humans; Hyperactivity; Mice; Mitomycin - toxicity; multidisciplinary; Picolinic Acids - toxicity; Repair; Scars; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-12234-1

Polymerase theta (Pol θ, gene name Polq ) is a widely conserved DNA polymerase that mediates a microhomology-mediated, error-prone, double strand break (DSB) repair pathway, referred to as Theta Mediated End Joining (TMEJ). Cells with homologous recombination deficiency are reliant on TMEJ for DSB repair. It is unknown whether deficiencies in other components of the DNA damage response (DDR) also result in Pol θ addiction. Here we use a CRISPR genetic screen to uncover 140 Polq synthetic lethal (PolqSL) genes, the majority of which were previously unknown. Functional analyses indicate that Pol θ/TMEJ addiction is associated with increased levels of replication-associated DSBs, regardless of the initial source of damage. We further demonstrate that approximately 30% of TCGA breast cancers have genetic alterations in PolqSL genes and exhibit genomic scars of Pol θ/TMEJ hyperactivity, thereby substantially expanding the subset of human cancers for which Pol θ inhibition represents a promising therapeutic strategy. Polymerase theta is a widely conserved DNA polymerase that mediates Theta Mediated End Joining. Here authors present a synthetic lethal CRISPR screen to identify DDR gene mutations that induce cellular addiction to Pol theta.