Fig. 4.

Synthetic genetic interactions of CTD phospho-site mutants. (A) Synthetically lethal pairs of alleles are highlighted in red boxes. Viable double mutants without a synthetic defect are indicated by plain green boxes. Viable double mutants that displayed ts or cs defects are annotated as such in their respective green boxes. The yellow boxes indicate severe synthetic growth defect (very sick). (B) S. pombe strains bearing the indicated csk1 or cdk9 alleles in combination with CTD WT or CTD-T4A alleles as specified were grown in liquid culture at 30 °C and assayed for acid phosphatase activity. Each datum in the bar graph is the average of assays using cells from at least three independent cultures ± SEM.