Schurter W, Holloway B W
Plasmid. 1987 Jan;17(1):61-4. doi: 10.1016/0147-619x(87)90010-2.
Tn7 transposes from the chromosome of Pseudomonas aeruginosa into the plasmid R68.45 with tandem IS21, at up to 400 times the frequency that it transposes into R68, which has only one copy of IS21. While R68::TN7 derivatives are stable, R68.45::Tn7 isolates undergo frequent deletions. Instability of R68.45 occurs whether Tn7 is inserted into the plasmid (cis configuration) or into the bacterial chromosome (trans configuration). The deletions of R68.45 start at the junction between the tandem IS21 copies and proceed clockwise, ending in the region of oriT. It appears that Tn7 and IS21 can mutually stimulate transposition of each other.
Tn7从铜绿假单胞菌染色体转移到带有串联IS21的质粒R68.45中，其转移频率高达转移到只有一个IS21拷贝的R68中的400倍。虽然R68::TN7衍生物是稳定的，但R68.45::Tn7分离株经常发生缺失。无论Tn7是插入到质粒中（顺式构型）还是插入到细菌染色体中（反式构型），R68.45都会发生不稳定性。R68.45的缺失从串联IS21拷贝之间的连接处开始，顺时针进行，终止于oriT区域。似乎Tn7和IS21可以相互刺激彼此的转座。
