Genetic implication for an interaction between release factor one and ribosomal protein L7/L12 in vivo

Strains with mutant alleles of the genes encoding release factor one (RF1), prfA, and ribosomal protein L7/L12, rplL, have been analyzed. The prfA1 allele has previously been shown to be associated with temperature sensitivity for growth at 43 degrees C and increased misreading of the nonsense codons UAG and UAA. Here we show that the prfA1 mutation is a nucleotide substitution that results in an arginine to proline change at amino acid position 137 in RF1. This alters the factor in a domain which may be involved in ribosome-binding. The rplL564 allele codes for a mutant form of protein L7/L12 that has a change in its conserved, translation-factor binding, domain. The rplL564 mutation suppresses the temperature sensitive phenotype and the increased translational misreading associated with the prfA1 allele, while other studied rplL mutant alleles do not. These data are consistent with an interaction between L7/L12 and RF1 in vivo.