Mode of selection and experimental evolution of antifungal drug resistance in Saccharomyces cerevisiae.
Mode of selection and experimental evolution of antifungal drug resistance in Saccharomyces cerevisiae.
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发表时间：
2003-04
期刊：
影响因子：
3.3
通讯作者：
James B. Anderson;C. Sirjusingh;A. Parsons;Charles Boone;Claire Wickens;L. Cowen;L. Kohn
中科院分区：
文献类型：
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作者：
James B. Anderson;C. Sirjusingh;A. Parsons;Charles Boone;Claire Wickens;L. Cowen;L. Kohn
我们发现，选择模式，突变的显性程度，和倍性的决定因素，在酵母抗真菌药物氟康唑的耐药性的演变。在实验1中，酵母菌群进行了逐步增加氟康唑浓度超过400代。在这种方案下，在相同的两个染色体区域中的两个突变在三个重复群体中平行地上升到高频率。这些突变对抗性的影响是半显性和加性的。这些突变中的第一个定位于PDR1，并导致ABC转运蛋白基因PDR5和SNQ2的过表达。这些突变具有意想不到的多效性效应，即降低野生型在最高浓度氟康唑下的剩余繁殖能力。在实验2中，酵母菌群受到单一的高浓度的氟康唑。在此方案下，一个单一的隐性突变出现在每个三个重复群体。在对约4700株存活缺失菌株进行的全基因组筛选中，13株被归类为对氟康唑耐药（ERG 3、ERG 6、YMR 102 C、YMR 099 C、YPL 056 C、ERG 28、OSH 1、SCS 2、CKA2、SML 1、YBR 147 W、YGR 283 C和YLR 407 W）。实验2中的突变均定位于ERG 3，导致编码药物靶标ERG 11的基因过表达，但不导致PDR 5和SNQ 2。实验1和2的二倍体杂种在氟康唑存在下比亲本更不适合。在实验2的变体中，单倍体比二倍体表现出更高的抗性频率，这表明显性程度和倍性是抗真菌药物抗性进化的重要因素。
We show that mode of selection, degree of dominance of mutations, and ploidy are determining factors in the evolution of resistance to the antifungal drug fluconazole in yeast. In experiment 1, yeast populations were subjected to a stepwise increase in fluconazole concentration over 400 generations. Under this regimen, two mutations in the same two chromosomal regions rose to high frequency in parallel in three replicate populations. These mutations were semidominant and additive in their effect on resistance. The first of these mutations mapped to PDR1 and resulted in the overexpression of the ABC transporter genes PDR5 and SNQ2. These mutations had an unexpected pleiotropic effect of reducing the residual ability of the wild type to reproduce at the highest concentrations of fluconazole. In experiment 2, yeast populations were subjected to a single high concentration of fluconazole. Under this regimen, a single recessive mutation appeared in each of three replicate populations. In a genome-wide screen of approximately 4700 viable deletion strains, 13 were classified as resistant to fluconazole (ERG3, ERG6, YMR102C, YMR099C, YPL056C, ERG28, OSH1, SCS2, CKA2, SML1, YBR147W, YGR283C, and YLR407W). The mutations in experiment 2 all mapped to ERG3 and resulted in the overexpression of the gene encoding the drug target ERG11, but not PDR5 and SNQ2. Diploid hybrids from experiments 1 and 2 were less fit than the parents in the presence of fluconazole. In a variation of experiment 2, haploids showed a higher frequency of resistance than diploids, suggesting that degree of dominance and ploidy are important factors in the evolution of antifungal drug resistance.