Fournier B, Truong-Bolduc Q C, Zhang X, Hooper D C
Infectious Disease Division and Medical Services, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114-2696, USA.
J Bacteriol. 2001 Apr;183(7):2367-71. doi: 10.1128/JB.183.7.2367-2371.2001.
NorA, a multidrug efflux pump in Staphylococcus aureus, protects the cell from multiple drugs, including quinolones. The flqB mutation (T-->G) in the 5' untranslated region upstream of norA causes norA overexpression of 4.9-fold in cis, as measured in norA::blaZ fusions. The transcriptional initiation site of norA was unchanged in mutant and wild-type strains, but the half-life of norA mRNA was increased 4.8-fold in the flqB mutant compared to the wild-type strain. Computer-generated folding of the first 68 nucleotides of the norA transcript predicts an additional stem-loop and changes in a putative RNase III cleavage site in the flqB mutant.
NorA是金黄色葡萄球菌中的一种多药外排泵，可保护细胞免受多种药物的影响，包括喹诺酮类药物。在norA的5'非翻译区上游的flqB突变（T→G）导致norA在顺式中过表达4.9倍，这是在norA::blaZ融合体中测量得到的。在突变株和野生型菌株中，norA的转录起始位点没有变化，但与野生型菌株相比，flqB突变株中norA mRNA的半衰期增加了4.8倍。norA转录本前68个核苷酸的计算机生成折叠预测，flqB突变体中会出现一个额外的茎环结构，并在假定的RNase III切割位点发生变化。
