Aguilera A
Institut für Mikrobiologie (Genetik), Technische Hochschule Darmstadt, Federal Republic of Germany.
Curr Genet. 1987;11(6-7):429-34. doi: 10.1007/BF00384603.
A mutant with a deletion covering the phosphoglucose isomerase gene PGI1, allele pgil delta, can only grow on a medium containing fructose and low concentrations of glucose whereas growth is completely inhibited by glucose concentrations higher than 0.4%. This was used to select suppressor mutants restoring growth on synthetic media with 2% glucose as the sole carbon source. One complementation group, SPG1, was defined by recessive mutations. The ability to grow on glucose media was strictly dependent on functional mitochondria. The generation time of the selected mutants on YEP glucose was 6-8 h. No ethanol was formed from glucose and the levels of respiration were very high. These phenotypes were also observed in single pgil delta mutants when growing on fructose media supplemented with 0.4% glucose. The other glycolytic enzymes, the enzymes of the glucose-6-phosphate oxidation pathway as well as catabolite repression were normal in suppressed pgil delta mutants. The suppressor mutation alone caused no abnormal phenotype. The results suggest that the spg1 suppressor mutations allow S. cerevisiae pgil delta mutant strains to grow on glucose by using the Pentose-P cycle in combination with unusual strong respiration.
一个缺失突变体，其缺失区域覆盖磷酸葡萄糖异构酶基因PGI1，等位基因pgilΔ，只能在含有果糖和低浓度葡萄糖的培养基上生长，而葡萄糖浓度高于0.4%时生长则完全受到抑制。利用这一特性筛选出了能在以2%葡萄糖作为唯一碳源的合成培养基上恢复生长的抑制突变体。一个互补群SPG1由隐性突变定义。在葡萄糖培养基上生长的能力严格依赖于功能性线粒体。所选突变体在YEP葡萄糖培养基上的代时为6 - 8小时。葡萄糖不产生乙醇，呼吸水平非常高。当在补充有0.4%葡萄糖的果糖培养基上生长时，在单个pgilΔ突变体中也观察到了这些表型。在被抑制的pgilΔ突变体中，其他糖酵解酶、6 - 磷酸葡萄糖氧化途径的酶以及分解代谢物阻遏均正常。单独的抑制突变不会导致异常表型。结果表明，spg1抑制突变通过将戊糖 - P循环与异常强烈的呼吸作用相结合，使酿酒酵母pgilΔ突变体菌株能够在葡萄糖上生长。
