Identifying suppressors of DNA damage hypersensitivity

Ataxia-telangiectasia (AT) and Fanconi anaemia (FA) are hereditary DNA-damage-response disorders (DDRDs) where a lack of DNA repair factors causes genome instability. On a cellular level, affected individuals display strongly increased sensitivity to DNA damage. Through an unbiased screening approach, I aim to identify suppressors of DNA damage hypersensitivity in AT- and FA-backgrounds. In brief, I will create haploid cells that carry gene deficiencies associated with either AT or FA and are therefore hypersensitive to specific types of DNA damage. These cells will be subjected to random insertional mutagenesis using a retroviral gene trap system, then treated with DNA damaging agents at doses that would normally kill all AT or FA cells. Gene traps in the resistant population will be localized by next-generation sequencing. This forward synthetic viability screen will thus identify genes whose disruption restores resistance to DNA damage in a particularly vulnerable background. Candidate genes will be tested for their roles in DNA damage repair as well as in the cellular pathogenesis of the respective DDRD, which I will investigate in engineered or patient-derived cell lines. Subsequently, I will extend these studies to mouse models of AT and FA, and to cancers with somatically acquired AT or FA defects.