Kans J A, Casadaban M J
Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637.
J Bacteriol. 1989 Apr;171(4):1904-14. doi: 10.1128/jb.171.4.1904-1914.1989.
The Tn3 transposon inserts at a reduced frequency into a plasmid already containing a copy of Tn3, a phenomenon known as transposition immunity. The cis-acting site on Tn3 responsible for immunity was mapped by deletions from each side to be within the terminal 38-base-pair sequence that is inversely repeated at the ends of Tn3. Two palindromic sequences are present in the essential part of this region. Some deletions conferred only partial immunity, and others conferred negative immunity. Multiple copies of partially immune ends conferred additional immunity. No other part of Tn3 was necessary for immunity.
Tn3转座子以较低频率插入到已经含有一个Tn3拷贝的质粒中，这种现象称为转座免疫。通过从两侧进行缺失作图，确定了Tn3上负责免疫的顺式作用位点位于末端38个碱基对的序列内，该序列在Tn3的末端反向重复。该区域的关键部分存在两个回文序列。一些缺失仅赋予部分免疫，而另一些则赋予负免疫。部分免疫末端的多个拷贝赋予额外的免疫。Tn3的其他部分对免疫不是必需的。
