Kholodii G Y, Mindlin S Z, Bass I A, Yurieva O V, Minakhina S V, Nikiforov V G
Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia.
Mol Microbiol. 1995 Sep;17(6):1189-200. doi: 10.1111/j.1365-2958.1995.mmi_17061189.x.
The complete nucleotide sequence of an 8447 bp-long mercury-resistance transposon (Tn5053) has been determined. Tn5053 is composed of two modules: (i) the mercury-resistance module and (ii) the transposition module. The mercury-resistance module carries a mer operon, merRTPFAD, and appears to be a single-ended relic of a transposon closely related to the classical mercury-resistance transposons Tn21 and Tn501. The transposition module of Tn5053 is bounded by 25 bp terminal inverted repeats and contains four genes involved in transposition, i.e. tniA, tniB, tniQ, and tniR. Transposition of Tn5053 occurs via cointegrate formation mediated by the products of the tniABQ genes, followed by site-specific cointegrate resolution. This is catalysed by the product of the tniR gene at the res region, which is located upstream of tniR. The same pathway of transposition is used by Tn402 (Tn5090) which carries the integron of R751. Transposition genes of Tn5053 and Tn402 are interchangeable. Sequence analysis suggests that Tn5053 and Tn402 are representatives of a new family of transposable elements, which fall into a recently recognized super-family of transposons including retroviruses, insertion sequences of the IS3 family, and transposons Tn552 and Tn7. We suggest that the tni genes were involved in the dissemination of integrons.
已确定一个长度为8447 bp的汞抗性转座子（Tn5053）的完整核苷酸序列。Tn5053由两个模块组成：（i）汞抗性模块和（ii）转座模块。汞抗性模块携带一个mer操纵子merRTPFAD，似乎是一个与经典汞抗性转座子Tn21和Tn501密切相关的转座子的单端遗迹。Tn5053的转座模块由25 bp的末端反向重复序列界定，包含四个参与转座的基因，即tniA、tniB、tniQ和tniR。Tn5053的转座通过由tniABQ基因产物介导的共整合体形成发生，随后进行位点特异性共整合体解析。这由位于tniR上游的res区域的tniR基因产物催化。携带R751整合子的Tn402（Tn5090）使用相同的转座途径。Tn5053和Tn402的转座基因是可互换的。序列分析表明，Tn5053和Tn402是一个新的转座元件家族的代表，它们属于最近被认可的转座子超家族，包括逆转录病毒、IS3家族的插入序列以及转座子Tn552和Tn7。我们认为tni基因参与了整合子的传播。
