Jobling M G, Ritchie D A
Department of Genetics, Univesity of Liverpool, U.K.
Gene. 1988 Jun 30;66(2):245-58. doi: 10.1016/0378-1119(88)90361-7.
The plasmid pMJ606 contains a 5-kb insert specifying resistance to tellurium salts (TeR) which was cloned from the large conjugative plasmid pMER610. Nucleotide sequence analysis of this insert has identified five open reading frames (ORFs). ORFs 1, 2, 4 and 5 correspond in terms of their predicted polypeptide products to the 41, 15.5, 22 and 23-kDa polypeptides, respectively, which are synthesised by the resistance determinant in maxicells. An additional ORF, ORF3, whose product has not been identified is predicted by the sequence data. The sequence of the presumptive polypeptide specified by ORF3 indicates a membrane location. The nucleotide and predicted amino acid sequences of ORF4 and ORF5 show considerable homology which is consistent with the duplication and minor divergence of an ancestral gene. ORFs 4 and 5 appear to retain the same function and while each can function separately and contribute to the resistance mechanism, the full level of wild-type resistance requires both genes to function. The transcriptional signals for the TeR determinant may be located beyond and 5' of the sequences cloned in pMJ606.
质粒pMJ606含有一个5kb的插入片段，该片段赋予对碲盐（TeR）的抗性，它是从大的接合性质粒pMER610中克隆而来的。对该插入片段的核苷酸序列分析已鉴定出五个开放阅读框（ORF）。ORF1、2、4和5在其预测的多肽产物方面分别对应于由最大细胞中的抗性决定簇合成的41、15.5、22和23kDa多肽。序列数据预测了另一个ORF，即ORF3，其产物尚未确定。由ORF3指定的推定多肽序列表明其位于膜上。ORF4和ORF5的核苷酸和预测氨基酸序列显示出相当大的同源性，这与一个祖先基因的复制和微小差异一致。ORF4和ORF5似乎保留相同的功能，虽然每个都可以单独发挥作用并有助于抗性机制，但野生型抗性的完整水平需要两个基因都发挥作用。TeR决定簇的转录信号可能位于pMJ606中克隆序列的下游和5'端之外。
