Hong Z, Mann P, Shaw K J, Didomenico B
Chemotherapy and Molecular Genetics, Schering-Plough Research Institute, Kenilworth, New Jersey 07033-0539.
Yeast. 1994 Aug;10(8):1083-92. doi: 10.1002/yea.320100810.
We have previously shown that mutations in the yeast KNR4 gene resulted in pleiotropic cell wall defects, including resistance to killer 9 toxin, elevated osmotic sensitivity to SDS and increased resistance to zymolyase, a (1-->3)-beta-glucanase. In this report, we further demonstrated that knr4 mutant cells were more permeable to a chromogenic substrate, X-GAL, suggesting that the mutant cell walls were leakier to certain non-permeable molecules. To determine if these defects resulted from structural changes in the cell walls, we analysed the alkali-insoluble cell wall components using HPLC assays developed for this purpose. Comparative analysis using four isogenic strains from a 'knr4 disrupted' tetrad demonstrated that mutant cell walls contained much less (1-->3)-beta-glucan and (1-->6)-beta-glucan; however, the level of chitin, a minor cell wall component, was found to be five times higher in the mutant strains compared to the wild-type strains. The data suggested that the knr4 mutant cell walls were dramatically weakened, which may explain the pleiotropic cell wall defects.
我们之前已经表明，酵母KNR4基因的突变会导致多效性细胞壁缺陷，包括对杀伤9毒素的抗性、对SDS的渗透压敏感性升高以及对（1→3）-β-葡聚糖酶溶壁酶的抗性增加。在本报告中，我们进一步证明，knr4突变体细胞对生色底物X-GAL的通透性更高，这表明突变体细胞壁对某些非渗透性分子的泄漏性更强。为了确定这些缺陷是否由细胞壁的结构变化引起，我们使用为此目的开发的HPLC分析方法分析了碱不溶性细胞壁成分。使用来自“knr4破坏”四分体的四个同基因菌株进行的比较分析表明，突变体细胞壁中（1→3）-β-葡聚糖和（1→6）-β-葡聚糖的含量要少得多；然而，发现作为次要细胞壁成分的几丁质水平在突变体菌株中比野生型菌株高五倍。数据表明，knr4突变体细胞壁显著减弱，这可能解释了多效性细胞壁缺陷。
