Andrup L, Bendixen H H, Jensen G B
National Institute of Occupational Health, Department of Toxicology and Biology, Copenhagen, Denmark.
Plasmid. 1995 May;33(3):159-67. doi: 10.1006/plas.1995.1017.
The Bacillus thuringiensis subsp. israelensis (Bti) plasmid pTX14-3 has been reported to contain a gene, mob14-3, with considerable homology to genes encoding mobilization proteins from other gram-positive bacteria. We have used the aggregation-mediated conjugation system recently discovered in Bti to compare the mobilization kinetics of different derivatives of plasmid pTX14-3. Plasmid pTX14-3 has been found to replicate by the rolling-circle mechanism and to contain a locus suppressing the formation of high-molecular-weight DNA. We found that deleting a DNA fragment containing this locus increased the transfer frequency about twofold. The mobilization frequency of the plasmid containing the intact mob14-3 gene did not indicate a mobilization-enhancing activity of the encoded polypeptide. However, the presence of the mob14-3 gene seemed to increase the stability of the plasmid in exponential growth.
据报道，苏云金芽孢杆菌以色列亚种（Bti）的质粒pTX14-3含有一个基因mob14-3，该基因与编码其他革兰氏阳性菌转移蛋白的基因具有相当高的同源性。我们利用最近在Bti中发现的聚集介导的接合系统，比较了质粒pTX14-3不同衍生物的转移动力学。已发现质粒pTX14-3通过滚环机制复制，并含有一个抑制高分子量DNA形成的位点。我们发现，删除包含该位点的DNA片段可使转移频率提高约两倍。含有完整mob14-3基因的质粒的转移频率并未表明所编码多肽具有增强转移的活性。然而，mob14-3基因的存在似乎提高了质粒在指数生长中的稳定性。
