Characterization of novel regulatory mechanism for the catabolic genes of aromatic compound degradation

为了确定乔氏红球菌（Rhodococcus jostii） RHA1中联苯（BP）分解代谢途径基因的转录调控机制，对iclr型转录调控基因tsdR进行了表征，该基因的转录受BP分解代谢双组分调控系统的控制。有或没有BP的tsdR缺失突变体的转录组分析结果表明，tsdR调控基因参与BP分解代谢。利用纯化的TsdR和含有tsdB和tsdT的2,6-二羟基苯甲酸酯（26DHB）分解代谢基因的启动子区域进行电泳迁移分析发现，TsdR与tsd启动子区域结合，并且这种结合被26DHB的加入所抑制。这些结果表明，TsdR作为tsd基因转录的抑制因子，26DHB作为效应分子与TsdR相互作用。

In order to identify the regulatory mechanism for the transcription of biphenyl (BP) catabolic pathway genes in Rhodococcus jostii RHA1, an IclR-type transcriptional regulator gene, tsdR, whose transcription is controlled by two-component regulatory system of BP catabolism, was characterized. The results of the transcriptome analysis of tsdR deletion mutant grown with or without BP suggesting that the TsdR-regulated genes are involved in the BP catabolism. Electrophoretic mobility shift assays using purified TsdR and the promoter regions of 2,6-dihydroxybenzaote (26DHB) catabolic genes containing tsdB and tsdT revealed that the TsdR binds to the tsd promoter regions and the bindings are inhibited by the addition of 26DHB. These results indicate that TsdR acts as a repressor for the transcription of tsd genes and 26DHB interacts with TsdR as an effector molecule.