Ljungquist E, Bertani L E
Mol Gen Genet. 1983;192(1-2):87-94. doi: 10.1007/BF00327651.
Fragments of DNA of the temperate phage P2, generated by treatment with the restriction enzyme PstI, have been cloned into the plasmid pBR322. One such fragment, which has its endpoints within phage genes T and C, carries the structural P2 int gene as well as its promoter and the phage att site. When introduced into a suitable bacterial host, the cloned fragment mediates the integration and excision of int- mutants of P2 and recombination within the phage att site in mixed infection. All these activities are independent of the orientation of the fragment within the plasmid. When introduced into minicells, the fragment produces, in addition to the products of genes D and U, a protein of 35-37,000 daltons identified as the int protein. A study of the map location of two amber int mutants, together with the sizes of the polypeptides they produce, indicates that the P2 int gene is transcribed from right to left on the P2 map, i.e. starting near gene C and proceeding toward att.
经限制性内切酶PstI处理产生的温和噬菌体P2的DNA片段已被克隆到质粒pBR322中。其中一个片段的端点位于噬菌体基因T和C内，它携带结构P2 int基因及其启动子以及噬菌体附着位点。当将该克隆片段导入合适的细菌宿主时，它介导P2 int突变体的整合和切除以及混合感染中噬菌体附着位点内的重组。所有这些活性都与片段在质粒中的方向无关。当将该片段导入微小细胞时，除了基因D和U的产物外，还产生一种分子量为35,000至37,000道尔顿的蛋白质，鉴定为int蛋白。对两个琥珀型int突变体的图谱定位及其产生的多肽大小的研究表明，P2 int基因在P2图谱上从右向左转录，即从基因C附近开始并向附着位点方向进行。
