Chiang S J, Jordan E, Clowes R C
Mol Gen Genet. 1982;187(2):187-94. doi: 10.1007/BF00331116.
Intermolecular transposition of Tn2660 into pCR1 was measured at 30 degrees C in recA- and recA+ hosts as between 2.6 and 5.5 X 10(-3), a similar value to that previously found for Tn3. No cointegrate structures were found under conditions where 10(4) transposition events occurred. Immunity to intermolecular transposition of Tn2660, similar to that found for Tn3 was demonstrated by showing that the above transposition frequency was reduced by a factor of between 10(-3) and 10(-4) when a mutant Tn2660 (resulting in the synthesis of a temperature-sensitive beta-lactamase) was present in the recipient plasmid. Intramolecular transposition of Tn3 was found to occur under the same conditions as previously demonstrated for Tn2660 giving rise to similar end products, in which the newly introduced Tn3 is oriented inversely to the resident Tn3 and the DNA sequence between the two transposons has been inverted. Thus, in all respects functional identity of the transposition activities of Tn3 and Tn2660 is shown, thereby identifying characteristics of intramolecular transposition that are not readily accommodated by current models of transposition.
在30摄氏度下，于recA -和recA +宿主中测量了Tn2660向pCR1的分子间转座，结果为2.6至5.5×10⁻³，这一数值与先前发现的Tn3相似。在发生10⁴次转座事件的条件下，未发现共整合结构。通过表明当受体质粒中存在突变型Tn2660（导致合成温度敏感型β-内酰胺酶）时，上述转座频率降低了10⁻³至10⁻⁴倍，证明了Tn2660对分子间转座具有类似于Tn3的免疫性。发现Tn3的分子内转座在与先前证明的Tn2660相同的条件下发生，产生类似的终产物，其中新引入的Tn3与常驻Tn3方向相反，且两个转座子之间的DNA序列发生了倒转。因此，在各个方面都显示出Tn3和Tn2660转座活性的功能同一性，从而确定了当前转座模型难以解释的分子内转座特征。
