DNA Damage Sensitivity Assays in Caenorhabditis elegans

C. elegans has served as a genetically tractable multicellular model system to examine DNA damage-induced genotoxic stress which threatens genome integrity. Importantly, the high degree of conservation shared between worms and humans offers the advantage that findings about DNA damage-induced cell cycle arrest/checkpoint response and DNA double-strand break repair in worms are applicable to human studies. Here, we describe simple DNA damage sensitivity assays to quantify the response of C. elegans to diverse types of DNA damaging agents. These assays have provided important insights into the mechanisms of function for factors such as ZTF-8 that are involved in DNA damage repair and response in the C. elegans germline. These DNA damage sensitivity assays rely on the straightforward readouts of either egg or larval lethality and involve the use of various DNA damaging agents. We use γ-irradiation (γ-IR), which produces DNA double-strand breaks (DSBs), camptothecin (CPT), which induces single-strand breaks, nitrogen mustard (HN₂), which produces interstrand crosslinks (ICLs), hydroxyurea (HU), which results in replication fork arrest thus preventing DNA synthesis, and UV-C, which causes photoproducts (pyrimidine dimers). See Table 1. Comparisons between the relative sensitivity/resistance observed in, for example, mutants compared to wild type, for various DNA damaging agents allows for inferences regarding potential repair pathways being affected.