Frameshifting at collided ribosomes is modulated by elongation factor eEF3 and by integrated stress response regulators Gcn1 and Gcn20

The yef3-fs1009 mutation suppresses frameshifting at CGA codon repeats when the frame quality control system is compromised by defects in MBF1 or RPS3. (A) Schematic of RFP and GLN4_(1–99)-(CGA)₄ + 1-GFP reporter used in these analyses. (B–E) The yef3-fs1009 mutation suppresses frameshifting caused by the mbf1-R89K mutation (B), by deletion of MBF1 (C), by the RPS3-K108N mutation (D) or by the RPS3-S104Y mutation (E). In each case, the yef3-fs1009 mutation results in significantly reduced levels of both frameshifted protein and protein per mRNA and in two cases results in small but significant reductions in mRNA. (**) P < 0.01 ≥ 0.001. (***) P < 0.001.