Antagonistic signals within the COX2 mRNA coding sequence control its translation in Saccharomyces cerevisiae mitochondria

Inhibition of translation by codons 15–25 is more dependent upon the mRNA sequence than the encoded peptide sequence. Nucleotide and peptide sequences for the COX2 portions of cox2(1,15–25,89–91)::ARG8^m and three derivative alleles, as well as for the prototrophic allele cox2(1,89–91)::ARG8^m, and phenotypes are shown. cox2–230::ARG8^m and cox2–231::ARG8^m shift the reading frame for codons 15–25 into the +1 and −1 frames, respectively. Inserted nucleotides are shown in bold, and the positions of insertions and deletions are denoted as “+1” and “−1.” The third allele, cox2–232::ARG8^m, introduces silent third nucleotide substitutions (underlined) into each codon in this region. Strains shown, from top to bottom: EHW155, EHW328–EHW330, and EHW154 (Table 1).