The rrp4-G226D mutant exhibits distinct negative genetic interactions with RNA exosome cofactor mutants that are not shared by the rrp40-W195R mutant. (A) Cartoon schematic of the budding yeast nuclear RNA exosome interacting with nuclear cofactors, Mpp6 and Rrp47, and the exoribonuclease Rrp6 (Schuller et al. 2018). (B) Double mutant cells containing rrp4-G226D and mpp6Δ, rrp47Δ, or rrp6Δ show impaired growth compared to single mutants at 30°C and 37°C. The double mutant cells (rrp4Δ with mpp6Δ, rrp47Δ, or rrp6Δ) containing control RRP4 or rrp4-G226D plasmid were serially diluted, spotted onto solid media, and grown at the indicated temperatures for 3 d. (C) Double mutant cells containing rrp40-W195R and mpp6Δ do not exhibit a change in growth compared to single mutants, whereas double mutant cells containing rrp40-W195R and rrp47Δ or rrp6Δ show impaired growth compared to single mutants at 37°C. The double mutant cells (rrp40Δ with mpp6Δ, rrp47Δ, or rrp6Δ) containing control RRP40 or rrp40-W195R plasmid were serially diluted, spotted onto solid media, and grown at indicated temperatures for 3 d.
