Stauffer G V, Stauffer L T
Department of Microbiology, University of Iowa, Iowa City 52242.
Mol Gen Genet. 1988 Sep;214(1):32-6. doi: 10.1007/BF00340175.
Using an Escherichia coli lac deletion strain lysogenized with lambda phage carrying a metF-lacZ gene fusion (lambda Flac), in which beta-galactosidase levels are dependent on metF gene expression, cis-acting mutations were isolated that affect regulation of the Salmonella typhimurium metF gene. The mutations were located in a region previously defined as the metF operator by its similarity to the E. coli metF operator sequence. Regulation of the metF gene was examined by measuring beta-galactosidase levels in E. coli strains lysogenized with the wild-type lambda Flac phage and mutant lambda Flac phage. The results suggest that the mutations disrupt the methionine control system mediated by the metJ gene product, but not the vitamin B12 control system mediated by the metH gene product. The results also demonstrate that negative control of the metF gene by the metH gene product and vitamin B12 is dependent on a functional metJ gene product.
利用携带metF-lacZ基因融合体（λFlac）的λ噬菌体溶原化的大肠杆菌lac缺失菌株，其中β-半乳糖苷酶水平取决于metF基因表达，分离出影响鼠伤寒沙门氏菌metF基因调控的顺式作用突变。这些突变位于先前因其与大肠杆菌metF操纵序列相似而被定义为metF操纵子的区域。通过测量用野生型λFlac噬菌体和突变型λFlac噬菌体溶原化的大肠杆菌菌株中的β-半乳糖苷酶水平来检测metF基因的调控。结果表明，这些突变破坏了由metJ基因产物介导的甲硫氨酸控制系统，但没有破坏由metH基因产物介导的维生素B12控制系统。结果还表明，metH基因产物和维生素B12对metF基因的负调控依赖于功能性的metJ基因产物。
