Nishi K, Yoshida M, Nishimura M, Nishikawa M, Nishiyama M, Horinouchi S, Beppu T
Department of Agricultural Chemistry, Faculty of Agriculture, University of Tokyo, Japan.
Mol Microbiol. 1992 Mar;6(6):761-9. doi: 10.1111/j.1365-2958.1992.tb01526.x.
Screening for leptomycin B (LMB)-resistant transformants in a gene library constructed in Schizosaccharomyces pombe with the chromosomal DNA of an LMB-resistant mutant of S. pombe and with multicopy plasmid pDB248' as the vector led to the isolation of a gene, named pmd1+, encoding a 1362-amino-acid protein. This protein showed great similarity in amino acid sequence to the mammalian P-glycoprotein encoded by the multidrug resistance gene, mdr, and the Saccharomyces cerevisiae a-factor transporter encoded by STE6. In addition, computer analyses predicted that the protein encoded by pmd1+ formed an intramolecular duplicated structure and each of the halves contained six transmembrane regions as well as two ATP-binding domains, as observed with the P-glycoproteins and the STE6 product. Consistent with this was that S. pombe cells containing the pmd1+ gene on a multicopy plasmid showed resistance not only to LMB but also to several cytotoxic agents. The pmd1 null mutants derived by gene disruption were viable and hypersensitive to these agents. All these data suggest that the pmd1+ gene encodes a protein that is a structural and functional counterpart of mammalian mdr proteins.
以粟酒裂殖酵母LMB抗性突变体的染色体DNA构建于粟酒裂殖酵母中的基因文库，以多拷贝质粒pDB248'为载体，筛选对莱普霉素B（LMB）抗性的转化体，从而分离出一个名为pmd1 +的基因，该基因编码一种含1362个氨基酸的蛋白质。该蛋白质的氨基酸序列与多药耐药基因mdr编码的哺乳动物P - 糖蛋白以及STE6编码的酿酒酵母α - 因子转运蛋白具有高度相似性。此外，计算机分析预测，pmd1 +编码的蛋白质形成分子内重复结构，且每个半部分包含六个跨膜区域以及两个ATP结合结构域，这与P - 糖蛋白和STE6产物的情况相同。与此一致的是，在多拷贝质粒上含有pmd1 +基因的粟酒裂殖酵母细胞不仅对LMB有抗性，而且对几种细胞毒性剂也有抗性。通过基因破坏产生的pmd1缺失突变体是可行的，但对这些试剂高度敏感。所有这些数据表明，pmd1 +基因编码的蛋白质是哺乳动物mdr蛋白的结构和功能对应物。
