Tsuchida S I, Kokubo H, Tasaka M, Fujisawa H
Department of Botany, Faculty of Science, Kyoto University, Japan.
Virology. 1996 Mar 1;217(1):332-7. doi: 10.1006/viro.1996.0120.
T3 and T7 phages package recombinant plasmids carrying DNA necessary for DNA packaging (the pac sequences) of T3 and T7, respectively. Packaging is specific between T3 and T7. The pac sequence has a bipartite structure, consisting of target sequences for processing of concatemeric DNA (pac C) and its left side flanking sequence containing a promoter for phage RNA polymerase (pac B). To determine the sequences responsible for the specificity of plasmid DNA packaging, plasmids chimeric for the pac B and pac C sequences of T3 and T7 were constructed. Analysis of packaging of the chimeric plasmid DNAs showed that pac B is responsible for the packaging specificity of T3 and T7 DNAs. Plasmids carrying the genetic right end of T3 and T7 DNA interfered with the growth of T3 and T7 phages, respectively. Interference was specific between T3 and T7. pac B and sequences between pac B and pac C, but not pac C, were responsible for the interference. The specificity of interference was determined by pac B and sequences responsible for interference were partially defined.
T3噬菌体和T7噬菌体分别包装携带T3和T7 DNA包装所需DNA（pac序列）的重组质粒。T3和T7之间的包装具有特异性。pac序列具有二分结构，由串联DNA加工的靶序列（pac C）及其左侧侧翼序列组成，该侧翼序列包含噬菌体RNA聚合酶的启动子（pac B）。为了确定负责质粒DNA包装特异性的序列，构建了T3和T7的pac B和pac C序列嵌合的质粒。对嵌合质粒DNA包装的分析表明，pac B负责T3和T7 DNA的包装特异性。携带T3和T7 DNA遗传右端的质粒分别干扰T3和T7噬菌体的生长。T3和T7之间的干扰具有特异性。pac B以及pac B和pac C之间的序列（而非pac C）负责干扰。干扰的特异性由pac B决定，负责干扰的序列部分已明确。
