SPECIALIZED TRANSDUCTION OF TETRACYCLINE RESISTANCE BY PHAGE-P22 IN SALMONELLA-TYPHIMURIUM .2. PROPERTIES OF A HIGH-FREQUENCY TRANSDUCING LYSATE
SPECIALIZED TRANSDUCTION OF TETRACYCLINE RESISTANCE BY PHAGE-P22 IN SALMONELLA-TYPHIMURIUM .2. PROPERTIES OF A HIGH-FREQUENCY TRANSDUCING LYSATE
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DOI：
10.1016/0042-6822(72)90442-4
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发表时间：
1972-01-01
期刊：
影响因子：
3.7
通讯作者：
OGATA, Y
中科院分区：
文献类型：
--
作者：
CHAN, RK;BOTSTEIN, D;OGATA, Y
用携带R因子222的鼠伤寒沙门氏菌LT-2株作为载体，用P22噬菌体转化LT-2菌株产生的特异性RP 22溶原，诱导产生四环素抗性（tetR）的高频转导（HFT）溶菌产物。HFT裂解物含有缺陷P22颗粒，称为P22 Tc-10，其不能生长或溶原化（即，transtransducetR）。然而，两个有缺陷的P22 Tc-10颗粒可以彼此协作以用于生长或用于溶原性（即，tetR的转导），在HFT裂解物中可以发现“野生型”噬菌体，其可以在单次感染时生长并且不再转导tetR，其频率为5 × 10− 5 PFU/颗粒。这些“野生型”的DNA中有5%也是整合缺陷的。在高感染复数下，用HFT裂解物制备的tetR转导子似乎类似于P22 Tc-10溶原细胞（即，为了解释这些观察结果，提出了一个模型，其中fortetRare基因插入P22 Tc-10前噬菌体中完整的P22基因组中。这样的插入的后果进行了讨论，关于噬菌体P22 DNA的结构和成功的DNA复制，噬菌体生长和溶原化的拓扑要求。
A high-frequency-transducing (HFT) lysate for tetracycline resistance (tetR) was obtained by inducing an unusualtetRP22 lysogen which had been made by transducingSalmonclla typhimuriumLT-2 totetRwith P22 phage grown on an LT-2 strain carrying the R factor 222. The HFT lystate contains defective P22 particles, called P22 Tc-10, which cannot grow or lysogenize (i.e., transducetetR) upon single infection. However, two defective P22 Tc-10 particles can cooperate with each other for growth or for lysogeny (i.e., transduction oftetR), “Wild-type” phages which can grow on single infection and which no longer transducetetRcan be found at a frequency of 5 × 10−5PFU/particle in the HFT lysate. Five percent of these “wild-type” phages are also integration deficient. At high multiplicities of infection thetetRtransductants made with an HFT lysate appear to be similar to a P22 Tc-10 lysogen (i.e., they are immune to P22 and yield HFT lysates upon induction); at low multiplicities of infection, many of thetetRtransductants aretetRP22 prophage deletions.To account for these observations, a model is proposed in which the genes fortetRare inserted into the intact P22 genome in the P22 Tc-10 prophage. The consequences of such an insertion are discussed with regard to the structure of phage P22 DNA and the topological requirements for successful DNA replication, phage growth, and lysogenization.