Characterization of the 450-kb linear plasmid in a polychlorinated biphenyl degrader, Rhodococcus sp strain RHA1
Characterization of the 450-kb linear plasmid in a polychlorinated biphenyl degrader, Rhodococcus sp strain RHA1
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DOI：
10.1128/aem.67.5.2021-2028.2001
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发表时间：
2001-05-01
影响因子：
4.4
通讯作者：
Fukuda, M
中科院分区：
文献类型：
--
作者：
Shimizu, S;Kobayashi, H;Fukuda, M
多氯联苯强降解菌红球菌RHA1具有多种联苯/多氯联苯降解基因，并含有大量的线形质粒，包括pRHL1(1100kb)、pRHL2(450kb)和pRHL3(330kb)，不同的降解基因主要分布在pRHL1和pRHL2质粒上。本研究测定了pRHL2的结构和功能特征，构建了pRHL2的物理图谱，并将降解酶基因bphB2、etd2、etbc、bphDEF、bphC2和bphC4定位在三个区域PRHL2在RHA1突变型衍生物之间以7.5×10(-5)接合子的频率在每个受体之间观察到转移。这些结果表明，该线性质粒可能是决定不同降解基因在罗氏球菌中繁殖的决定因素，pRHL2的末端仅被克隆和测序。PRHL2的左右两端都有3个碱基的完美末端反向重复序列，它们之间的相似性(同源性)不像已知的放线菌线性复制子那样。用pRHL2末端探针进行Southern杂交分析表明，pRHL2的右侧末端与pRHL1和pRHL3末端相似，凝胶位移实验中两个末端片段的滞留表明pRHL2的每个末端都与一个蛋白质相连。我们认为pRHL2具有倒子末端，正如先前对链霉菌线性复制子的报道一样。
A strong polychlorinated biphenyl (PCB) degrader, Rhodococcus sp, strain RHA1, has diverse biphenyl/PCB degradative genes and harbors huge linear plasmids, including pRHL1 (1,100 kb), pRHL2 (450 kb), and pRHL3 (330 kb), The diverse degradative genes are distributed mainly on the pRHL1 and pRHL2 plasmids, In this study, the structural and functional characteristics of pRHL2 were determined, We constructed a physical map of pRHL2, and the degradative enzyme genes, including bphB2, etbD2, etbC, bphDEF, bphC2, and bphC4, were localized in three regions, Conjugal transfer of pRHL2 between RHA1 mutant derivatives was observed at a frequency of 7.5 x 10(-5) transconjugant per recipient. These results suggested that the linear plasmid is a possible determinant of propagation of the diverse degradative genes in rhodococci, The termini of pRHL2 mere cloned and sequenced. The left and right termini of pRHL2 had 3-bp perfect terminal inverted repeats and were not as similar to each other (64% identity) as the known actinomycete linear replicons are. Southern hybridization analysis with pRHL2 terminal probes suggested that the right terminus of pRHL2 is similar to pRHL1 and pRHL3 termini, Retardation of both terminal fragments in the gel shift assay indicated that each terminus of pRHL2 is linked to a protein. We suggest that pRHL2 has invertron termini, as has been reported previously for Streptomyces linear replicons.