Localization and functional analysis of transposon mutations in regulatory genes of the TOL catabolic pathway
Localization and functional analysis of transposon mutations in regulatory genes of the TOL catabolic pathway
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TOL分解代谢途径调控基因转座子突变的定位和功能分析
DOI：
10.1128/jb.154.2.676-685.1983
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发表时间：
1983
影响因子：
3.2
通讯作者：
K. Timmis
中科院分区：
文献类型：
--
作者：
F. Franklin;P. Lehrbach;R. Lurz;B. Rueckert;M. Bagdasarian;K. Timmis
TOL质粒pWW0-161的突变衍生物已被鉴定和鉴定，它含有分解代谢途径的xylS和xylR调节基因中的TN5插入。这两个基因一起位于TOL的1.5到3.0千碱基的片段上，恰好位于代谢裂解途径酶基因的下游。根据目前TOL分解代谢途径调控模型的预测，在xylS突变菌中，间甲基苯甲醇诱导了具有代表性的苯甲醇脱氢酶(苯甲醇脱氢酶)，而在xylR突变菌中，间甲基苯甲醇不能诱导，而在xylR突变体中，邻苯二酚2，3-加氧酶(邻苯二酚2，3-加氧酶)被间甲苯磺酸诱导，而在xylS突变体中则不诱导。然而，出乎意料的是，间甲基苯甲醇不能诱导XylS突变体中的邻苯二酚2，3-加氧酶，而苯甲醇和苯甲酸酯却能诱导。这些结果表明，TOL质粒编码的分解代谢途径的表达至少受三个调控元件的调控，其中两个调控元件(xylS和xylR基因的产物)在甲基化的碳氢化合物和醇诱导下的低途径中相互作用，其中一个只对非甲基化底物起反应。
Mutant derivatives of the TOL plasmid pWW0-161, containing Tn5 insertions in the xylS and xylR regulatory genes of the catabolic pathway, have been identified and characterized. The two genes are located together on a 1.5- to 3.0-kilobase segment of TOL, just downstream of genes of the enzymes of the meta-cleavage pathway. As predicted by a current model for regulation of the TOL catabolic pathway, benzyl alcohol dehydrogenase, a representative enzyme of the upper (hydrocarbon leads to carboxylic acid) pathway, was induced by m-methylbenzyl alcohol in xylS mutant bacteria but not in a xylR mutant, whereas catechol 2,3-oxygenase, a representative enzyme of the lower (meta-cleavage) pathway, was induced by m-toluate in a xylR mutant but not in the xylS mutants. Unexpectedly, however, catechol 2,3-oxygenase was not induced by m-methylbenzyl alcohol in xylS mutants but was induced by benzyl alcohol and benzoate. These results indicate that expression of the TOL plasmid-encoded catabolic pathway is regulated by at least three control elements, two of which (the products of the xylS and xylR genes) interact in the induction of the lower pathway by methylated hydrocarbons and alcohols and one of which responds only to nonmethylated substrates.