Xiong A, Jayaswal R K
Department of Biological Sciences, Illinois State University, Normal, Illinois 61790-4120, USA.
J Bacteriol. 1998 Aug;180(16):4024-9. doi: 10.1128/JB.180.16.4024-4029.1998.
A DNA fragment conferring resistance to zinc and cobalt ions was isolated from a genomic DNA library of Staphylococcus aureus RN450. The DNA sequence analysis revealed two consecutive open reading frames, designated zntR and zntA. The predicted ZntR and ZntA showed significant homology to members of ArsR and cation diffusion families, respectively. A mutant strain containing the null allele of zntA was more sensitive to zinc and cobalt ions than was the parent strain. The metal-sensitive phenotype of the mutant was complemented by a 2.9-kb DNA fragment containing zntR and zntA. An S. aureus strain harboring multiple copies of zntR and zntA showed an increased resistance to zinc. The resistance to zinc in the wild-type strain was inducible. Transcriptional analysis indicated that zntR and zntA genes were cotranscribed. The zinc uptake studies suggested that the zntA product was involved in the export of zinc ions out of cells.
从金黄色葡萄球菌RN450的基因组DNA文库中分离出一段赋予对锌离子和钴离子抗性的DNA片段。DNA序列分析揭示了两个连续的开放阅读框，分别命名为zntR和zntA。预测的ZntR和ZntA分别与ArsR家族成员和阳离子扩散家族成员具有显著同源性。含有zntA无效等位基因的突变菌株比亲本菌株对锌离子和钴离子更敏感。突变体的金属敏感表型被包含zntR和zntA的2.9 kb DNA片段互补。携带多个zntR和zntA拷贝的金黄色葡萄球菌菌株对锌的抗性增强。野生型菌株对锌的抗性是可诱导的。转录分析表明zntR和zntA基因是共转录的。锌摄取研究表明zntA产物参与锌离子从细胞中输出。
