Genome-wide screens for DNA damage response factors. (a) Definition of CGI. Fitness of an ORF-AID strain (normalized colony size, Materials and methods) measured under four conditions: control (no perturbation), in the presence of 5-Ph-IAA (to induce degradation of the AID-tagged protein), GA, or both. Grey bar, expected fitness in the double perturbation condition (product of the fitness from the single perturbation conditions) in the absence of a CGI. Magenta and green bars, examples of negative and positive CGIs. (b) Top, overlap between chemical-genetic interactors identified with the AID-v2 library and previously identified resistance genes for MMS (Chang et al., 2002), CPT, or HU (Parsons et al., 2004). Essential factors identified with the AID-v2 library were excluded from the comparison. Bottom, frequency of OsTIR1-dependent degradation phenotypes in the AID-v1 library for the indicated sets of genes. (c) Heatmap of negative chemical-genetic interactors with MMS, CPT, or HU, as in Fig. 4 d. Gene names, essential genes and significant interactors (circles) with each GA are indicated. (d and e) 10-fold serial dilutions of the indicated strains from the AID-v2 library, a wild type (wt) and a RAD52 knockout on the indicated media. Essential genes are marked in magenta (d).