Bertani G
Microbial Genetics Laboratory, Karolinska Institutet, Stockholm, Sweden.
Mol Gen Genet. 1975;136(2):107-37. doi: 10.1007/BF00272034.
Several types of viable chromosomal deletions of bacteriophage P2 were isolated. One type gives the immunity insensitive phenotype and may extend to the genes for the immunity repressor (C) and for integrative recombination (int). Two other types delete genes (old and fun) known to be active in the lysogenic state. For such deletion mutants the relationship between particle density and DNA length was established. The deletions were located in respect to previously mapped genes and the results were compared with electron microscopical studies (by Inman and collaborators) of the P2 chromosome. It is concluded that the best representation of the genetic map of P2 is circular. The cohesive ends of the linear P2 DNA molecule are most likely formed between genes old and Q. Except for the neighborhood of gene old, the previously published, linear genetic map of P2 (Lindahl) is colinear with the melting map of the P2 chromosome (Inman). Preliminary evidence for some specific recombination event often accompanying integrative recombination between phage chromosomes is presented.
分离出了几种噬菌体P2的存活染色体缺失类型。其中一种类型表现出免疫不敏感表型，可能延伸至免疫阻遏物（C）基因和整合重组（int）基因。另外两种类型缺失了已知在溶原状态下活跃的基因（old和fun）。对于此类缺失突变体，确定了颗粒密度与DNA长度之间的关系。根据先前定位的基因确定了缺失位置，并将结果与P2染色体的电子显微镜研究（由英曼及其合作者进行）进行了比较。得出的结论是，P2遗传图谱的最佳表示形式是环状的。线性P2 DNA分子的粘性末端很可能在old基因和Q基因之间形成。除了old基因附近外，先前发表的P2线性遗传图谱（林达尔）与P2染色体的解链图谱（英曼）是共线的。还提供了一些证据，表明某些特定的重组事件常伴随噬菌体染色体之间的整合重组。
