Mediator subunits mdt-15 and cdk-8 are required for cadmium and zinc stress responses.

[A] The Venn diagram depicts the overlap between genes downregulated in the mdt-15(tm2182) mutant and genes induced by cadmium (identified in [43]). Statistical significance was assessed by Fisher’s exact test. Shared genes include cdr-1 and mtl-2, which are known to function in cadmium biology [40,41]. See S1 Table for details. [B] The Venn diagram depicts the overlap between genes downregulated in the cdk-8(tm1238) mutant and genes induced by cadmium. Statistical significance was assessed by Fisher’s exact test. Shared genes include cdr-1 and numr-1, which are known to function in cadmium biology [40,42,44]. See S1 Table for details. [C-D] qRT-PCR analysis of zinc and cadmium-responsive genes in wild-type (WT) and cdk-8(tm1238) mutant worms grown on 100μM cadmium for 4 hours [C] or on 200μM zinc for 16 hours [D]. Graphs show fold induction, normalized to the average of unsupplemented WT mRNA levels. Error bars: SEM (n = 3 independent repeats). Statistical analysis: * p < 0.05, unpaired t-test comparing WT supplemented worms to WT supplemented worms, except for comparisons indicated by lines (note, only significant or near-significant (p < 0.075) values are shown).