Eustice D C, Wakem L P, Wilhelm J M, Sherman F
J Mol Biol. 1986 Mar 20;188(2):207-14. doi: 10.1016/0022-2836(86)90305-0.
The five suppressors SUP35, SUP43, SUP44, SUP45 and SUP46, each mapping at a different chromosomal locus in the yeast Saccharomyces cerevisiae, suppress a wide range of mutations, including representatives of all three types of nonsense mutations, UAA, UAG and UGA. We have demonstrated that ribosomes from the four suppressors SUP35, SUP44, SUP45 and SUP46 translate polyuridylate templates in vitro with higher errors than ribosomes from the normal stain, and that this misreading is substantially enhanced by the antibiotic paromomycin. Furthermore, ribosomal subunit mixing experiments established that the 40 S ribosomal subunit, and this subunit only, is responsible for the higher levels of misreading. Thus, the gene products of SUP35, SUP44, SUP45 and SUP46 are components of the 40 S subunit or are enzymes that modify the subunit. In addition, a protein from the 40 S subunit of the SUP35 suppressor has an altered electrophoretic mobility; this protein is distinct from the altered protein previously uncovered in the 40 S subunit of the SUP46 suppressor. In contrast to the ribosomes from the four suppressors SUP35, SUP44, SUP45 and SUP46, the ribosomes from the SUP43 suppressor do not significantly misread polyuridylate templates in vitro, suggesting that this locus may not encode a ribosomal component or that the misreading is highly specific.
五种抑制基因SUP35、SUP43、SUP44、SUP45和SUP46，各自定位于酿酒酵母的不同染色体位点，可抑制多种突变，包括所有三种类型的无义突变UAA、UAG和UGA的代表突变。我们已经证明，来自SUP35、SUP44、SUP45和SUP46这四种抑制基因的核糖体在体外翻译聚尿苷酸模板时比正常菌株的核糖体具有更高的错误率，并且这种错读会被抗生素巴龙霉素显著增强。此外，核糖体亚基混合实验表明，40S核糖体亚基，且只有该亚基，是导致更高错读水平的原因。因此，SUP35、SUP44、SUP45和SUP46的基因产物是40S亚基的组成部分，或者是修饰该亚基的酶。另外，来自SUP35抑制基因的40S亚基中的一种蛋白质具有改变的电泳迁移率；这种蛋白质与先前在SUP46抑制基因的40S亚基中发现的改变的蛋白质不同。与来自SUP35、SUP44、SUP45和SUP46这四种抑制基因的核糖体相反，来自SUP43抑制基因的核糖体在体外不会显著错读聚尿苷酸模板，这表明该位点可能不编码核糖体成分，或者错读具有高度特异性。
