eEF3 competes with Hel2 and Gcn1 to regulate frameshifting at CGA codon repeats. (A) Schematic of RFP and GLN4(1–99)-(CGA)4 + 1-GFP reporter used in these analyses. (B) The suppression of frameshifting due to the yef3-fs1009 mutation is nearly lost in mutants lacking both HEL2 and GCN1. Similar effects are observed with removal of HEL2 alone. (C,D) Complementation of mutants with plasmid-born YEF3 (C) or GCN1 (D). (E) High levels of frameshifting are observed in hel2Δ gcn1Δ mutants despite the presence of a functional MBF1 gene. (F) The high level of frameshifting in strains lacking Mbf1 is not substantially affected by deletion of HEL2 (gray), GCN1 (orange), or HEL2 and GCN1 (green). (G) The yef3-fs1009 mutation suppresses the high levels of frameshifting in the gcn1Δ hel2Δ mutant. Frameshifting suppression in the yef3-fs1009 mutant is complemented with addition of a CEN plasmid bearing YEF3.
