Badenas C, Madrid C, Juárez A
Departamento de Microbiologia, Facultad de Biologia, Universidad de Barcelona, Spain.
Can J Microbiol. 1994 Jul;40(7):597-601. doi: 10.1139/m94-095.
We report the occurrence of Tn5 secondary transpositions in Escherichia coli HB101 hha::Tn5(pANN202-312). Tn5-induced hha mutants (hemolysin overproducers) segregated at high frequency either hemolysin-negative clones or clones showing the parental hemolytic phenotype (reduced hemolysin production). Secondary transpositions of Tn5 appeared to be responsible for the phenotypes of both types of derivatives. The hemolysin-negative clones no longer harboured Tn5 in the hha gene, but rather Tn5 was in the hly genes of the hemolytic plasmid pANN202-312. The derivatives that recovered the parental hemolytic phenotype contained a single copy of Tn5 in a chromosomal location different from that of hha. Both kinds of transpositional events appeared to restore the function of the hha gene.
我们报道了在大肠杆菌HB101 hha::Tn5(pANN202 - 312)中发生的Tn5二次转座。Tn5诱导的hha突变体（溶血素过量产生菌）高频分离出溶血素阴性克隆或表现出亲本溶血表型（溶血素产生减少）的克隆。Tn5的二次转座似乎是这两种类型衍生物表型的原因。溶血素阴性克隆在hha基因中不再含有Tn5，而是Tn5存在于溶血性质粒pANN202 - 312的hly基因中。恢复亲本溶血表型的衍生物在与hha不同的染色体位置含有单拷贝的Tn5。这两种转座事件似乎都恢复了hha基因的功能。
