Ribosomal control of translational fidelity in Podospora anserina: A suppressor and an antisuppressor affecting the paromomycin-induced misreading in vitro

Summary The hypersensitivity to paromomycin dis played by the su _1–60 suppressor, which was thought to be a ribosomal ambiguity mutation, was used to isolate a new antisuppressor, AS ₇₁. This antisuppressor is not specific for ribosomal suppressors, since it is able to act on putative tRNA-type suppressors. Compared to the wild-type, the AS _7-1 mutation produces an increased resistance to paromomycin. In addition, it was found to stop the sporulation process. In the polyuridylic acid-dependant assay, the paromomycin induced misreading was shown to be higher on su _1–60 ribosomes and lower on ribosomes from AS _7–1 mutant and AS _7S-1-su _1–60 double mutant than on wild-type ribosomes. These data confirm that su _1–60 and AS _7-1 mutants are ribosomal mutants involved in the control of translational fidelity.