Feng X, Ou L T, Ogram A
Department of Crop and Soil Sciences, Washington State University, Pullman 99164-6420, USA.
Plasmid. 1997;37(3):169-79. doi: 10.1006/plas.1997.1289.
Sphingomonas sp. CFO6 (a member of the alpha group of Proteobacteria) was isolated from a Washington soil by enrichment on the insecticide carbofuran as a sole source of carbon and energy. This strain has been shown to harbor five plasmids, at least some of which are required for catabolism of carbofuran. Rearrangements, deletions, and loss of individual plasmids resulting in the loss of the carbofuran-degrading phenotype were observed following treatment with heat or introduction of Tn5. Several putative insertion sequence elements of different sizes were cloned from these plasmids by trapping in pUCD800, a positive selection vector for isolation of transposable elements. Three of the most common putative IS elements (designated IS1412, IS1487, and IS1488) in the clone library were of different sizes and cross-hybridize with each other. An element hybridizing with IS1412, IS1487, and IS1488 was mobilized during growth of CFO6 at 42 degrees C and inserted into one of CFO6's plasmids (pCFO4), corresponding to a deletion in the plasmid and a loss of catabolic function. IS1412 was completely sequenced and its sequence analyzed. IS1412 is 1656 bp in length and possesses terminal partially matched inverted repeats of unequal length (17 and 18 bp). In addition, IS1412 contains an open reading frame which encodes a putative transposase with significant homology to the putative transposases of IS1380 from Acetobacter pasteurianus, HRS1 from Bradyrhizobium japonicum, and IS1247 from Xanthobacter autotrophicus. These related IS elements form part of a family of common IS elements distributed among members of the alpha group of the Proteobacteria.
鞘氨醇单胞菌属菌株CFO6（变形菌门α亚群的一员）是从华盛顿州的土壤中分离得到的，其通过以杀虫剂克百威作为唯一碳源和能源进行富集培养。已证明该菌株含有5种质粒，其中至少一些质粒是克百威分解代谢所必需的。在用热或导入Tn5处理后，观察到个别质粒发生重排、缺失并导致克百威降解表型丧失。通过捕获于pUCD800（一种用于分离转座元件的阳性选择载体），从这些质粒中克隆了几个不同大小的推定插入序列元件。克隆文库中最常见的三种推定IS元件（命名为IS1412、IS1487和IS1488）大小不同且相互交叉杂交。在CFO6于42℃生长期间，与IS1412、IS1487和IS1488杂交的一个元件被激活，并插入到CFO6的一个质粒（pCFO4）中，这与质粒中的一个缺失以及分解代谢功能丧失相对应。对IS1412进行了全序列测定并分析了其序列。IS1412长度为1656 bp，具有长度不等的末端部分匹配反向重复序列（17和18 bp）。此外，IS1412包含一个开放阅读框，其编码一种推定转座酶，该转座酶与来自巴氏醋杆菌的IS1380、来自日本慢生根瘤菌的HRS1以及来自自养黄色杆菌的IS1247的推定转座酶具有显著同源性。这些相关的IS元件构成了分布在变形菌门α亚群成员中的常见IS元件家族的一部分。
