Skip to main content
. 1999 Jul 6;96(14):8046–8051. doi: 10.1073/pnas.96.14.8046

Figure 4.

Figure 4

Expression of an amino-terminal domain of mtRNA polymerase suppresses the rpo41Δ3 mutant phenotype. Portions of the RPO41 locus that conferred growth of GS125 on YPG at 37°C are diagrammed in A the same as in Fig. 1. All of the isolates contained the RPO41 promoter (bent arrow). The upstream endpoint is indicated by negative numbers in parentheses, indicating the distance upstream of the A of the AUG start codon for RPO41. The amount of genomic DNA downstream of the AUG start codon is given by the positive numbers in parentheses. The number in parentheses next to the positive values indicates the number of amino acids (aa) of mtRNA polymerase that is predicted to be expressed from each isolate. (B) A truncated mtRNA polymerase peptide is expressed in suppressor plasmid-containing strains. Whole-cell protein (lanes 1 and 2) and protein from a purified mitochondrial fraction (lanes 3 and 4) was isolated from yeast strains that either did (+) or did not (−) contain the suppressor plasmid harboring the smallest complementing fragment (the first 533 RPO41 codons) and subjected to Western analysis. GS129, which expresses both the RPO41 and rpo41Δ3 alleles, is shown in lanes 1 and 3. The rpo41Δ3 strain (GS125) harboring the suppressor plasmid is shown in lanes 2 and 4. The truncated mtRNA polymerase protein (≈57 kDa) expressed in the suppressor-containing strain is indicated by the double-headed arrow. The wild-type (wt) and rpo41Δ3-encoded (Δ3) mtRNA polymerase are indicated with arrows (note the absence of wild-type mtRNA polymerase in lane 2). Protein molecular mass standards are indicated on the left. (C) Expression of the precise mtRNA polymerase peptide missing in the rpo41Δ3 allele suppresses the temperature-sensitive petite phenotype in trans. Shown are the following strains grown on YPG medium at the nonpermissive temperature (36°C): 1, GS122(RPO41); 2, GS128(rpo41); 3, GS125(rpo41Δ3)+YEp352; 4, GS125(rpo41Δ3)+YEp-Δ3EXP; 5, GS125(rpo41Δ3)+ original suppressor plasmid (encoding amino acids 1–533 of mtRNA polymerase).