Hutter B, Dick T
Institute of Molecular and Cell Biology, 30 Medical Drive, 117609, Singapore, Singapore.
FEMS Microbiol Lett. 2000 Jul 15;188(2):141-6. doi: 10.1111/j.1574-6968.2000.tb09185.x.
Upon depletion of oxygen, the obligate aerobe mycobacteria switch from growth to a state of non-replicating persistence or dormancy. Here, we report the first functional analysis of a dormancy-dependent mycobacterial promoter in Mycobacterium bovis BCG. Promoter probing using a 'lacZ reporter detected a dormancy-inducible promoter activity upstream of the coding sequence for the putative nitrite extrusion protein NarK2. Primer extension analysis mapped a transcriptional start point 47 bp upstream of the narK2 start codon. Deletion analysis revealed that the sequence -222 to -133 bp upstream from the transcriptional start point was required for basal and dormancy-inducible reporter expression. The sequence +1 to +47 downstream of the transcriptional start point had a strong inhibitory effect on the level of dormancy-induced beta-galactosidase activity. The identification of apparent activating and inhibiting regions suggests that the narK2 promoter is at least under dual control.
在氧气耗尽时，专性需氧菌分枝杆菌从生长状态转变为非复制性持续存在或休眠状态。在此，我们报告了卡介苗中一个依赖休眠的分枝杆菌启动子的首次功能分析。使用“lacZ报告基因”进行启动子探测，在假定的亚硝酸盐外排蛋白NarK2编码序列上游检测到了休眠诱导型启动子活性。引物延伸分析确定了转录起始点位于narK2起始密码子上游47 bp处。缺失分析表明，转录起始点上游-222至-133 bp的序列是基础和休眠诱导型报告基因表达所必需的。转录起始点下游+1至+47的序列对休眠诱导的β-半乳糖苷酶活性水平有强烈的抑制作用。明显的激活和抑制区域的鉴定表明，narK2启动子至少受双重控制。
