Flores C, Qadri M I, Lichtenstein C
Imperial College of Science, Technology and Medicine, Centre for Biotechnology, London, UK.
Nucleic Acids Res. 1990 Feb 25;18(4):901-11. doi: 10.1093/nar/18.4.901.
A region of DNA sequence of the bacterial transposon Tn7, which is required for transposition, has been determined. This DNA sequence completes an 8351 base pair (bp) region containing five long open reading frames (ORF's) that correspond to the genetically defined genes, tnsA, B, C, D and E, required for Tn7 transposition. All of the ORF's are oriented in the same direction, ie. inward from the element's right end. The genes are in a very compact arrangement with the presumed initiation codons never more than two bases beyond the preceding termination codon. Domains with similarity to the helix-turn-helix genre of Cro-like, sequence specific DNA binding sites occur within the deduced amino acid (a.a.) sequence of the TnsA, TnsB, TnsD and TnsE proteins. Translation of the tnsC ORF reveals strong homology to a consensus sequence for nucleotide binding sites as well as a region of similarity to a transcriptional activator (MalT). No striking a.a. sequence similarity to other DNA recombinases is observed. The possible roles of these proteins in Tn7 transposition is discussed in light of the analysis presented.
已确定细菌转座子Tn7转座所需的一段DNA序列区域。该DNA序列完善了一个8351碱基对（bp）的区域，该区域包含五个长开放阅读框（ORF），它们对应于Tn7转座所需的基因tnsA、B、C、D和E，这些基因已通过遗传学方法确定。所有的ORF都按相同方向排列，即从元件右端向内。这些基因排列非常紧密，推测的起始密码子与前一个终止密码子之间的距离从不超过两个碱基。在TnsA、TnsB、TnsD和TnsE蛋白的推导氨基酸（a.a.）序列中存在与Cro样螺旋-转角-螺旋类型的序列特异性DNA结合位点相似的结构域。tnsC ORF的翻译显示与核苷酸结合位点的共有序列有很强的同源性，以及与转录激活因子（MalT）相似的区域。未观察到与其他DNA重组酶有明显的氨基酸序列相似性。根据所提供的分析讨论了这些蛋白在Tn7转座中的可能作用。
