Figure 3

Modularity in buffering growth against HU inhibition is exemplified by genes with related functions having similar strength of interactions. AUGC is plotted vs HU concentration in all cases. (a) Genes of the RAD52 epistasis group. Note the uniformly strong synergistic interaction (see Figure 1c), with the exception of RAD59. (b) Genes of the vacuolar H⁺-ATPase. Note the additive interactions (see Figure 1b). (c) Genes involved in vacuolar trafficking. The stronger interactions are shown in green. (d) Assorted examples of antagonistic interactions (see text and Additional data file 12). Note that gene deletions often, in general, antagonize the HU phenotype at concentrations where the growth inhibitory effect of the deletion is greater than the inhibitory effect of HU on the reference strain (see Figure 1d) [28]. REF, reference strain BY4741 (see Materials and methods).