In a background of apoptosis-deficient cells in imaginal discs, X-irradiation results in tumorigenic phenotypes, including overgrowth of targeted cells within the disc and delamination of the epithelium (see FBhh0001040). The additional effects of reduced function of genes involved in DNA repair have been assessed. RNAi-mediated reduction of okr (orthologous to human RAD54L) or spn-A (orthologous to human RAD51) enhance the tumorigenic phenotypes; these genes are required for homologous recombination repair of DNA double-strand breaks in G2. In contrast, loss-of-function mutation of a gene required for nonhomologous end-joining repair in G1, the ligase DNAlig4, has no effect.
[updated Jun. 2019 by FlyBase; FBrf0222196]