MOLECULAR-CLONING, MAPPING, AND REGULATION OF PHO REGULON GENES FOR PHOSPHONATE BREAKDOWN BY THE PHOSPHONATASE PATHWAY OF SALMONELLA-TYPHIMURIUM LT2
MOLECULAR-CLONING, MAPPING, AND REGULATION OF PHO REGULON GENES FOR PHOSPHONATE BREAKDOWN BY THE PHOSPHONATASE PATHWAY OF SALMONELLA-TYPHIMURIUM LT2
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DOI：
10.1128/jb.177.22.6411-6421.1995
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发表时间：
1995-11-01
影响因子：
3.2
通讯作者：
WANNER, BL
中科院分区：
文献类型：
--
作者：
JIANG, WH;METCALF, WW;WANNER, BL
存在两种途径用于膦酸酯的碳-磷（C-P）键的裂解，C-P裂解酶途径和膦酸酯酶途径。先前证明大肠杆菌携带仅用于C-P裂解酶途径的基因（命名为phn），而产气肠杆菌携带用于两种途径的基因（K. S.李，W。W. Metcalf和B，L，Wanner，J. Bacteriol. 174：2501-2510，1992）。相反，这里显示鼠伤寒沙门氏菌LT 2仅携带磷酸酶途径的基因。S.通过大肠杆菌Delta phn突变体的互补克隆鼠伤寒沙门氏菌磷酸酶途径。这些途径的基因被证明是不同源的，并位于不同的染色体区域。色葡萄typhimurium phn位点位于10 min附近; coliphn基因位于93 min附近，鼠伤寒沙门氏菌phn基因簇长约7.2kb，基因融合分析表明，该基因簇由两个（或多个）不同转录的基因或操纵子组成。与大肠杆菌phn基因座一样，S.鼠伤寒沙门氏菌phn基因座在Pi限制条件下被激活，并受Pho调节子控制。这一点通过适当的E. coli突变株，并构建了S.在phoB和pst基因座中具有损伤的鼠伤寒突变体，其分别是激活和抑制Pho调节子基因表达所需的。互补研究表明，S.鼠伤寒phn基因座可能包括膦酸盐转运基因和C-P键断裂催化基因。
Two pathways exist for cleavage of the carbon-phosphorus (C-P) bond of phosphonates, the C-P lyase and the phosphonatase pathways. It was previously demonstrated that Escherichia coli carries genes (named phn) only for the C-P lyase pathway and that Enterobacter aerogenes carries genes for both pathways (K.-S. Lee, W. W. Metcalf, and B, L, Wanner, J. Bacteriol. 174:2501-2510, 1992). In contrast, here it is shown that Salmonella typhimurium LT2 carries genes only for the phosphonatase pathway. Genes for the S. typhimurium phosphonatase pathway were cloned by complementation of E, coli Delta phn mutants. Genes for these pathways were proven not to be homologous and to lie in different chromosomal regions. The S. typhimurium phn locus lies near 10 min; the E. coli phn locus lies near 93 min, The S, typhimurium phn gene cluster is about 7.2 kb in length and, on the basis of gene fusion analysis, appears to consist of two (or more) genes or operons that are divergently transcribed. Like that of the E, coli phn locus, the expression of the S. typhimurium phn locus is activated under conditions of Pi limitation and is subject to Pho regulon control. This was shown both by complementation of the appropriate E. coli mutants and by the construction of S. typhimurium mutants with lesions in the phoB and pst loci, which are required for activation and inhibition of Pho regulon gene expression, respectively. Complementation studies indicate that the S. typhimurium phn locus probably includes genes both for phosphonate transport and for catalysis of C-P bond cleavage.