Merryweather A, Barth P T, Wilkins B M
J Bacteriol. 1986 Jul;167(1):12-7. doi: 10.1128/jb.167.1.12-17.1986.
The role of the DNA primase of IncP plasmids was examined with a derivative of RP4 containing Tn7 in the primase gene (pri). The mutant was defective in mediating bacterial conjugation, with the deficiency varying according to the bacterial strains used as donors and recipients. Complementation tests involving recombinant plasmids carrying cloned fragments of RP4 indicated that the primase acts to promote some event in the recipient cell after DNA transfer and that this requirement can be satisfied by plasmid primase made in the donor cell. It is proposed that the enzyme or its products or both are transmitted to the recipient cell during conjugation, and the role of the enzyme in the conjugative processing of RP4 is discussed. Specificity of plasmid primases was assessed with derivatives of RP4 and the IncI1 plasmid ColIb-P9, which is known to encode a DNA primase active in conjugation. When supplied in the donor cell, neither of the primases encoded by these plasmids substituted effectively in the nonhomologous conjugation system. Since ColIb primase provided in the recipient cell acted weakly on transferred RP4 DNA, it is suggested that the specificity of these enzymes reflects their inability to be transmitted via the conjugation apparatus of the nonhomologous plasmid.
利用在引发酶基因（pri）中含有Tn7的RP4衍生物，研究了IncP质粒DNA引发酶的作用。该突变体在介导细菌接合方面存在缺陷，缺陷程度因用作供体和受体的细菌菌株而异。涉及携带RP4克隆片段的重组质粒的互补试验表明，引发酶在DNA转移后作用于促进受体细胞中的某些事件，并且供体细胞中产生的质粒引发酶可以满足这一需求。有人提出，在接合过程中，该酶或其产物或两者都被传递到受体细胞中，并讨论了该酶在RP4接合过程中的作用。用RP4衍生物和IncI1质粒ColIb-P9评估了质粒引发酶的特异性，已知ColIb-P9编码一种在接合中具有活性的DNA引发酶。当在供体细胞中提供时，这些质粒编码的引发酶在非同源接合系统中均不能有效替代。由于在受体细胞中提供的ColIb引发酶对转移的RP4 DNA作用较弱，因此表明这些酶的特异性反映了它们无法通过非同源质粒的接合装置进行传递。
