Goebel W, Lindenmaier W, Pfeifer F, Schrempf H, Schelle B
Mol Gen Genet. 1977 Nov 29;157(2):119-29. doi: 10.1007/BF00267389.
The miniR1-(Rsc)-plasmids which derive from the copy mutant R1drd-19B2 (pKN102) are non-conjugative extrachromosomal elements which can not be co-transferred by various transfer factors to recipient strains under standard mating conditions. The attempts to mobilize Rsc11 by F'lac lead to transconjugants carrying F'lac::Tn3 with Tn3 mainly inserted into the lac operon. In addition it can be shown that Rsc11 can become inserted as a complete unit into the transfer factor giving rise to rather unstable recombinant intermediates. Dissociation of these intermediates may lead to alterations of the original plasmids. The Tn3 part of Rsc13 can be enlarged or deleted by in vitro manipulations. In vitro insertion of EcoRI-fragments into an EcoRI+ site of Tn3 leads to new transposable units which can be transposed to the RTF part of R1. This new genetic entity can be stably integrated into the chromosome of E. coli by integrative suppression of a dnaAts-mutation. Deletions at one end or the central region of Tn3 abolish the capability of transposition. However, the Rsc-plasmids containing the deleted Tn3 can still be inserted into the transfer factor as complete units. The resulting recombinants are unstable leading after dissociation in some cases to new plasmids with altered properties.
源自复制突变体R1drd - 19B2（pKN102）的miniR1-(Rsc)-质粒是非接合型的染色体外元件，在标准交配条件下，它们不能被各种转移因子共同转移到受体菌株中。用F'lac动员Rsc11的尝试导致产生携带F'lac::Tn3的转接合子，其中Tn3主要插入到乳糖操纵子中。此外，可以证明Rsc11能够作为一个完整单元插入转移因子中，从而产生相当不稳定的重组中间体。这些中间体的解离可能导致原始质粒发生改变。Rsc13的Tn3部分可以通过体外操作进行扩增或缺失。将EcoRI片段体外插入Tn3的EcoRI +位点会产生新的可转座单元，这些单元可以转座到R1的RTF部分。通过对dnaAts突变的整合抑制，这种新的遗传实体可以稳定地整合到大肠杆菌的染色体中。在Tn3一端或中央区域的缺失会消除转座能力。然而，含有缺失Tn3的Rsc质粒仍可作为完整单元插入转移因子中。产生的重组体不稳定，在某些情况下解离后会导致具有改变特性的新质粒。
