Distribution of gamma-hexachlorocyclohexane-degrading genes on three replicons in Sphingobium japonicum UT26.
Distribution of gamma-hexachlorocyclohexane-degrading genes on three replicons in Sphingobium japonicum UT26.
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DOI：
10.1111/j.1574-6968.2005.00096.x
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发表时间：
2006-03
影响因子：
2.1
通讯作者：
Y. Nagata;M. Kamakura;Ryo Endo;Ryo Miyazaki;Y. Ohtsubo;M. Tsuda
中科院分区：
文献类型：
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作者：
Y. Nagata;M. Kamakura;Ryo Endo;Ryo Miyazaki;Y. Ohtsubo;M. Tsuda
Sphingobium japonicum（原Sphingomonas paucimobilis）UT 26利用重要的杀虫剂γ-六氯环己烷作为唯一的碳源和能源。在以前的研究中，我们分离并表征了UT 26的六个结构基因（linA至linF）和一个调控基因（linR），用于将γ-六氯环己烷降解为β-酮己二酸。本研究中我们的分析表明，UT 26基因组由3.6 Mb、670 kb和185 kb的三个大的环状复制子组成。3.6 Mb和670 kb的复制子分别具有一个和两个拷贝的16 S核糖体RNA基因，这些复制子分别被指定为染色体（Chr）I和II。Chr Ⅰ是携带dnaA基因的一条主染色体。将γ-六氯环己烷转化为2，5-二氯氢醌的前三个lin基因（linA至linC）分散在Chr I上。185 kb质粒pCHQ 1携带用于将2，5-二氯氢醌转化为马来酰乙酸的linRED操纵子，并接合转移到另一种鞘氨醇单胞菌菌株中。编码马来酰乙酸还原酶的linF基因位于Chr II上。这些结果表明，γ-六氯环己烷完全降解的基因分散在UT 26的三个大复制子上。
Sphingobium japonicum (formerly Sphingomonas paucimobilis) UT26 utilizes the important insecticide gamma-hexachlorocyclohexane as a sole source of carbon and energy. In previous studies, we isolated and characterized six structural genes (linA to linF) and one regulatory gene (linR) of UT26 for the degradation of gamma-hexachlorocyclohexane to beta-ketoadipate. Our analysis in this study indicated that the UT26 genome consists of three large circular replicons of 3.6 Mb, 670 kb, and 185 kb. The 3.6 Mb and the 670 kb replicons had one and two copies, respectively, of the 16S ribosomal RNA gene, and these replicons were designated as chromosomes (Chr) I and II, respectively. Chr I was indicated to be a main chromosome carrying the dnaA gene. The first three lin genes, linA to linC, for conversion of gamma-hexachlorocyclohexane to 2,5-dichlorohydroquinone, were dispersed on Chr I. The 185 kb plasmid, pCHQ1, carried the linRED operon for the conversion of 2,5-dichlorohydroquinone to maleylacetate and was conjugatively transferred to another sphingomonad strain. The linF gene encoding maleylacetate reductase was located on Chr II. These results indicated that the genes for the complete gamma-hexachlorocyclohexane degradation are dispersed on the three large replicons of UT26.