Sarikaya Aysegul Topal, Akman Gokhan, Temizkan Guler
Istanbul University, Faculty of Science, Department of Moleuclar Biology and Genetics, and Instanbul University Research and Application Center for Biotechnology and Genetic Engineering, 34118 Vezneciler, Istanbul, Turkey.
Mol Biotechnol. 2006 Feb;32(2):139-46. doi: 10.1385/MB:32:2:139.
We isolated and characterized a nickel (Ni2+)-resistant mutant (GA1) of Schizosaccharomyces pombe. This mutant strain displayed resistance to both Ni2+ and Zn2+, but not to Cd2+, Co2+, and Cu2+. The growth rate of GA1 increased proportionally with increasing Mg2+ concentrations until 50 mM Mg2+. The GA1 mutation phenotype suggests a defect in Mg2+ uptake. Sequence analysis of the GA1 open reading frame (ORF) O13779, which is homologous to the prokaryotic and eukaryotic CorA Mg2+ transport systems, revealed a point mutation at codon 153 (ccc to acc) resulting in a Pro153Thr substitution in the N-terminus of the CorA domain. Our results provide novel genetic information about Ni2+ resistance in fission yeast. Specifically, that reducing Mg2+ influx through the CorA Mg2+ transport membrane protein confers Ni2+ resistance in S. pombe. We also report that Ni2+ ion detoxification of the fission yeast is related to histidine metabolism and pH.
我们分离并鉴定了粟酒裂殖酵母的一种耐镍（Ni2+）突变体（GA1）。该突变菌株对Ni2+和Zn2+均表现出抗性，但对Cd2+、Co2+和Cu2+不具有抗性。GA1的生长速率随着Mg2+浓度增加至50 mM Mg2+而呈比例增加。GA1的突变表型表明其Mg2+摄取存在缺陷。对与原核和真核CorA Mg2+转运系统同源的GA1开放阅读框（ORF）O13779进行序列分析，发现在密码子153处存在一个点突变（ccc突变为acc），导致在CorA结构域的N端发生Pro153Thr替换。我们的结果提供了关于裂殖酵母中Ni2+抗性的新遗传信息。具体而言，通过CorA Mg2+转运膜蛋白减少Mg2+内流可使粟酒裂殖酵母产生Ni2+抗性。我们还报告说，裂殖酵母的Ni2+离子解毒与组氨酸代谢和pH值有关。
