Dual Two-Component Regulatory Systems Are Involved in Aromatic Compound Degradation in a Polychlorinated-Biphenyl Degrader, Rhodococcus jostii RHA1
Dual Two-Component Regulatory Systems Are Involved in Aromatic Compound Degradation in a Polychlorinated-Biphenyl Degrader, Rhodococcus jostii RHA1
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DOI：
10.1128/jb.00429-10
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发表时间：
2010-07
影响因子：
3.2
通讯作者：
Hisashi Takeda;Jun Shimodaira;Kiyoshi Yukawa;N. Hara;D. Kasai;K. Miyauchi;E. Masai;M. Fukuda
中科院分区：
文献类型：
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作者：
Hisashi Takeda;Jun Shimodaira;Kiyoshi Yukawa;N. Hara;D. Kasai;K. Miyauchi;E. Masai;M. Fukuda
摘要革兰氏阳性多氯联苯降解菌约氏红球菌RHA1通过与联苯共代谢降解多氯联苯。由bphS1和bphT1编码的双组分BphS1T1系统(以前称为bPHS和bphT)负责bphAaAbAcAdC1B1、etbAa1Ab1CbphD1、etbAa2Ab2AcD2、etbAdbphB2和etbD1这五个基因簇的转录诱导，它们构成了联苯/多氯联苯降解的多个酶系统。编码BphS2和BphT2的bphS2和bphT2基因分别与BphS1(92%)和BphT1(97%)基本相同。BphS2T2在包括苯、甲苯、乙苯、二甲苯、异丙苯和氯代苯在内的多种芳烃存在下，诱导宿主红球红球菌IAM1399中bphAa启动子的激活，与BphS1T1一样有效。BphS2T2的底物光谱与BphS1T1相同，只是联苯是BphS1T1的底物。BphS2T2与BphS1T1一样有效地激活了联苯/多氯联苯降解酶基因簇的五个启动子的转录。BphS1、bphS2、bphT1和bphT2基因的靶向性破坏表明，所有这些基因都参与了RHA1在芳香族化合物上的生长。构建了含有bphS1和bphT2的杂交系统，以及含有bphS2和bphT1的杂交系统，两个系统都对bphAa启动子进行了诱导激活，表明存在交叉通讯。这些结果表明，RHA1不仅使用多个酶系统，而且还使用双重调节系统来降解联苯/多氯联苯。将包括bphS2T2的序列与含有bphS1T1的序列和其他罗氏杆菌降解物中的相应序列进行比较，表明bphS2T2可能起源于bphS1T1。
ABSTRACT A Gram-positive polychlorinated-biphenyl (PCB) degrader, Rhodococcus jostii RHA1, degrades PCBs by cometabolism with biphenyl. A two-component BphS1T1 system encoded by bphS1 and bphT1 (formerly bphS and bphT) is responsible for the transcription induction of the five gene clusters, bphAaAbAcAdC1B1, etbAa1Ab1CbphD1, etbAa2Ab2AcD2, etbAdbphB2, and etbD1, which constitute multiple enzyme systems for biphenyl/PCB degradation. The bphS2 and bphT2 genes, which encode BphS2 and BphT2, virtually identical to BphS1 (92%) and BphT1 (97%), respectively, were characterized. BphS2T2 induced the activation of the bphAa promoter in a host, Rhodococcus erythropolis IAM1399, in the presence of a variety of aromatics, including benzene, toluene, ethylbenzene, xylenes, isopropylbenzene, and chlorinated benzenes, as effectively as BphS1T1. The substrate spectrum of BphS2T2 was the same as that of BphS1T1, except for biphenyl, which is a substrate only for BphS1T1. BphS2T2 activated transcription from the five promoters of biphenyl/PCB degradation enzyme gene clusters as effectively as BphS1T1. The targeted disruptions of the bphS1, bphS2, bphT1, and bphT2 genes indicated that all these genes are involved in the growth of RHA1 on aromatic compounds. The hybrid system with bphS1 and bphT2 and that with bphS2 and bphT1 were constructed, and both systems conducted induced activation of the bphAa promoter, indicating cross-communication. These results indicated that RHA1 employs not only multiple enzyme systems, but also dual regulatory systems for biphenyl/PCB degradation. Comparison of the sequences, including bphS2T2, with the bphS1T1-containing sequences and the corresponding sequences in other rhodococcal degraders suggests that bphS2T2 might have originated from bphS1T1.