The Yeast Ribosomal Protein Rpl1b Is Not Required for Respiration

Previously, Segev and Gerst found that mutants in any of the four ribosomal protein genes rpl1b, rpl2b, rps11a, or rps26b had a petite phenotype-i.e., the mutants were deficient in respiration. Strikingly, mutants of their paralogs rpl1a, rpl2a, rps11b, and rps26a were grande-i.e., competent for respiration. It is remarkable that these paralogs should have opposite phenotypes, because three of the paralog pairs (Rpl1a/Rpl1b, Rpl2a/Rpl2b, Rps11a/Rps11b) are 100% identical to each other in terms of their amino acid sequences, while Rps26a and Rps26b differ in 2 amino acids out of 119. However, while attempting to use this paralog-specific petite phenotype in an unrelated experiment, I found that the rpl1b, rpl2b, rps11a, and rps26b deletion mutants are competent for respiration, contrary to the findings of Segev and Gerst.