Chemical synthetic lethality is obtained when inhibition of a gene product is lethal to cells which present other mutations.
Fig. 3c d illustrates the effect of intermediate values of C. Most of the benefit of late-acting lethality is obtained at values of C = 0.7, in other words the effectiveness of the proposed strategy is not particularly sensitive to imperfect larval competitiveness.
Because of the high lethality, dKO mice were obtained exclusively by breeding double heterozygous mice to avoid any selection of potential modifiers.
For larval lethality assays, embryos were obtained by bleaching adult worms with freshly mixed 20% household bleach and 0.5 N NaOH for 10 min. Embryos were then rinsed twice in M9 and rotated in M9 at room temperature (∼23°C) overnight to allow hatching.
When we expressed UAS.Dsh with MS1096.Gal4 we found near-absolute lethality (11 experimental flies were obtained from 1298 pupae - an eclosion rate of 0.84%).
About 12,500 M1 plants were obtained, showing 50% lethality at seedling stage.
Similar rescue results by dTip60WT were obtained for dTip60RNAi induced lethality [5] as well as using a second ubiquitous driver Act5c (Table S1).
Similar results were obtained when we attributed a lethality score to every somatic mutation using CADD29.
In all cases, viable Top2 m/ Top2 Df35; P[Top2-w +]/+ adults were obtained (Table S3), confirming that lethality was due to mutations in Top2.
However, when these CKO females and males were mated to produce the second generation, only 2 pups per litter were obtained, indicating high rates of embryonic lethality in the second generation (Figure 1A right).
