Parish T, Stoker N G
Department of Clinical Sciences, London School of Hygiene and Tropical Medicine, UK.
FEMS Microbiol Lett. 1997 Sep 1;154(1):151-7. doi: 10.1111/j.1574-6968.1997.tb12637.x.
Expression from a 2.3 kb region upstream of the inducible acetamidase gene from Mycobacterium smegmatis was shown to be upregulated by acetamide. A DNA fragment containing the start of the M. smegmatis hisD gene was cloned in front of the promoter, such that the antisense message was produced. When this construct was induced in vivo, the bacteria became phenotypically histidine auxotrophs; this auxotrophy was restored by histidine supplementation. Auxotrophy was not observed under non-induced conditions. Antisense mutagenesis may be useful for observing the phenotypic inactivation of specific mycobacterial genes, and an inducible system such as that described would allow the study of essential genes.
耻垢分枝杆菌诱导型乙酰胺酶基因上游2.3 kb区域的表达被证明受乙酰胺上调。将包含耻垢分枝杆菌hisD基因起始位点的DNA片段克隆到启动子前，从而产生反义信使。当该构建体在体内被诱导时，细菌在表型上变成组氨酸营养缺陷型；补充组氨酸可恢复这种营养缺陷。在未诱导条件下未观察到营养缺陷。反义诱变可能有助于观察特定分枝杆菌基因的表型失活，并且如所描述的诱导系统将允许对必需基因进行研究。
