Lauf U, Müller C, Herrmann H
Institut für Genetik und Biochemie, Ernst-Moritz-Arndt-Universität, Greifswald, Germany.
Mol Gen Genet. 1998 Oct;259(6):674-8. doi: 10.1007/s004380050862.
Genes for (methyl)phenol degradation in Pseudomonas putida strain H (phl genes) are located on the plasmid pPGH1. Adjacent to the phl catabolic operon we identified a cryptic transposon, Tn5501, of the Tn3 family (class II transposons). The genes encoding the resolvase and the transposase are transcribed in the same direction, as is common for the Tn501 subfamily. The enzymes encoded by Tn5501, however, show only the overall homology characteristic for resolvases/integrases and transposases of Tn3-type transposons. Therefore it is likely that Tn5501 is not a member of one of the previously defined subfamilies. Inactivation of the conditional lethal sacB gene was used to detect transposition of Tn5501. While screening for transposition events we found another transposon integrated into sacB in one of the sucrose-resistant survivors. This element, Tn5502, is a composite transposon consisting of Tn5501 and an additional DNA fragment. It is flanked by inverted repeats identical to those of Tn5501 and the additional fragment is separated from the Tn5501 portion by an internal repeat (identical to the left terminal repeat). Transposition of phenol degradation genes could not be detected. Analysis of sequence data revealed that the phl genes are not located on a Tn5501-like transposon.
恶臭假单胞菌H菌株中（甲基）苯酚降解基因（phl基因）位于质粒pPGH1上。在phl分解代谢操纵子附近，我们鉴定出一个Tn3家族（II类转座子）的隐蔽转座子Tn5501。编码解离酶和转座酶的基因转录方向相同，这是Tn501亚家族的常见情况。然而，Tn5501编码的酶仅显示出Tn3型转座子的解离酶/整合酶和转座酶的总体同源特征。因此，Tn5501很可能不是先前定义的亚家族之一的成员。利用条件致死性sacB基因的失活来检测Tn5501的转座。在筛选转座事件时，我们在一个蔗糖抗性存活菌株中发现另一个转座子整合到sacB中。这个元件Tn5502是一个复合转座子，由Tn5501和一个额外的DNA片段组成。它两侧是与Tn5501相同的反向重复序列，额外片段与Tn5501部分由一个内部重复序列（与左端末端重复序列相同）隔开。未检测到苯酚降解基因的转座。序列数据分析表明，phl基因不在类似Tn5501的转座子上。
