Lawley Trevor D, Gordon G Scott, Wright Andrew, Taylor Diane E
Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2R3.
Mol Microbiol. 2002 May;44(4):947-56. doi: 10.1046/j.1365-2958.2002.02938.x.
We used the LacO/GFP-LacI system to label and visualize the IncP beta plasmid R751 fluorescently during conjugative transfer between live donor and recipient bacteria. Comparisons of R751 in conjugative and non-conjugative conditions have allowed us to identify key localizations and movements associated with the initiation of conjugative transfer in the donor and the establishment of R751 in the recipient. A survey of successful mating pairs demonstrates that close physical contact between donor and recipient bacteria is required for DNA transfer and that regions of intimate contact can occur at any location on the donor or recipient cell membrane. The transferred DNA is positioned at the characteristic centre or quarter-cell position after conversion to a double-stranded molecule in the recipient cell. Initial duplication of plasmids often results in an asymmetric distribution of plasmid foci. Symmetric localization (either at centre or at 1/4 and 3/4 cell lengths) occurs only after a significant lag, presumably reflecting the time required to synthesize the plasmid-encoded partitioning proteins.
我们使用LacO/GFP-LacI系统在活的供体菌和受体菌之间进行接合转移期间对IncPβ质粒R751进行荧光标记和可视化观察。对处于接合和非接合条件下的R751进行比较，使我们能够确定与供体中接合转移起始以及受体中R751建立相关的关键定位和移动。对成功配对的调查表明，供体菌和受体菌之间紧密的物理接触是DNA转移所必需的，并且紧密接触区域可出现在供体或受体细胞膜的任何位置。转移的DNA在受体细胞中转化为双链分子后位于特征性的中心或四分之一细胞位置。质粒的初始复制通常会导致质粒焦点的不对称分布。对称定位（在中心或在细胞长度的1/4和3/4处）仅在显著延迟后才会出现，这大概反映了合成质粒编码的分区蛋白所需的时间。
