Parker Christopher, Meyer Richard J
Section of Molecular Genetics and Microbiology, University of Texas at Austin, Austin, TX 78712-1095, USA.
Mol Microbiol. 2002 Nov;46(3):761-8. doi: 10.1046/j.1365-2958.2002.03195.x.
Plasmid selection and strand replacement synthesis in donor cells during conjugative transfer was examined by a procedure involving electroporation of test plasmid DNA, containing a base pair mismatch, into donor cells prior to mating. Multiple copies of the plasmid were transferred from a donor cell that allowed vegetative replication of the plasmid. Under conditions non-permissive for vegetative replication, there were further rounds of transfer after a lag period. Strand replacement in the donor did not depend solely on the initiation mechanism for vegetative replication, indicating a conjugation-specific mechanism was also available. The lag period between first and second rounds of transfer argues against the transfer of multiple copies into recipients by the spooling of copies generated on a master molecule by rolling-circle replication.
通过一种程序对接合转移过程中供体细胞中的质粒选择和链置换合成进行了检测，该程序包括在交配前将含有碱基对错配的测试质粒DNA电穿孔导入供体细胞。质粒的多个拷贝从允许质粒进行营养复制的供体细胞中转移。在不允许营养复制的条件下，经过一段延迟期后会有进一步的转移轮次。供体中的链置换并不完全依赖于营养复制的起始机制，这表明还存在一种接合特异性机制。第一轮和第二轮转移之间的延迟期与通过滚环复制在主分子上产生的拷贝的缠绕将多个拷贝转移到受体细胞的观点相悖。
