COINTEGRATE FORMATION MEDIATED BY TN9 .2. ACTIVITY OF IS1 IS MODULATED BY EXTERNAL DNA-SEQUENCES
COINTEGRATE FORMATION MEDIATED BY TN9 .2. ACTIVITY OF IS1 IS MODULATED BY EXTERNAL DNA-SEQUENCES
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DOI：
10.1016/s0022-2836(83)80227-7
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发表时间：
1983-01-01
影响因子：
5.6
通讯作者：
GALAS, DJ
中科院分区：
文献类型：
--
作者：
CHANDLER, M;GALAS, DJ
研究了IS 1在供体复制子中的位置和取向对IS 1转座活性的影响。研究表明，复合转座子Tn 9中的IS 1在形成质粒共整合体方面具有不同的活性。将Tn 9克隆（与132个碱基对的侧翼DNA一起）到pBR 322中的几个位点，并产生这些质粒的各种衍生物，用作质粒融合实验中的供体分子。使这些pBR 322-Tn 9质粒与接合的F-衍生质粒形成共整合体，并分离出大量独立形成的共整合体。Tn 9的2个IS 1元件的相对活性通过检查共整合物的结构以确定共整合物形成中每个IS 1的使用频率来估计。IS 1活性可以通过供体质粒中相邻DNA序列的转录活性来调节。定向到IS 1的转录抑制其活性。这一假说的实验证据是通过观察到相邻转录启动子的缺失减轻了对IS 1活性的抑制作用而得到的。
The effect on the transposition activity of IS1 of the position and orientation of the element in the donor replicon was studied. Previous studies show that the IS1 in the compound transposon Tn9 have different activities in forming plasmid cointegrates. Tn9 was cloned (together with 132 base-pairs of flanking DNA) into several sites in pBR322 and created various derivatives of these plasmids to be used as donor molecules in plasmid fusion experiments. These pBR322-Tn9 plasmids were allowed to form cointegrates with a conjugative, F-derived plasmid, and a large collection of independently formed cointegrates was isolated. The relative activities of the 2 IS1 elements of Tn9 were estimated by examining the structures of the cointegrates for the frequency of usage of each of the IS1 in cointegrate formation. IS1 activity may be modulated by the transcription activity of adjacent DNA sequences in the donor plasmids. Transcription directed into an IS1 inhibits its activity. Confirmatory evidence for this hypothesis is provided by the observation that deletion of adjacent promoters of transcription relieves the inhibitory effect on IS1 activity.