Childs J D
Mutat Res. 1977 Aug;44(2):165-76. doi: 10.1016/0027-5107(77)90074-4.
Sixteen conditional lethal mutants of bacteriophage T4D have been isolated which grow on Escherichia coli CR63 (a su+ streptomycin-sensitive K12 strain) but are restricted by CR/s (a streptomycin-resistant derivative of CR63). These mutants have been given the prefix str. Four of these mutants are amber and 12 appear to be missense. Eleven of the 12 missense mutants appear to be "pseudo-amber" (i.e. they are restricted by a su- E. coli B strain but not by a su- K12 strain); the other missense mutant was not restricted by either B or K12. The str mutations mapped in 12 different genes. Most were clustered in a region of early genes (gene 56 to gene 47). Fifty-eight amber and 10 "pseudo-amber" mutants isolated previously for their inability to grow on E. coli B were tested for restriction by CR/s. All the amber mutants grew normally on CR/s, whereas all 10 "pseudo-amber" mutants were restricted by CR/s. This implies that the phenotype of the "pseudo-amber" mutants is the result of a ribosomal difference between the permissive host CR63 and the restrictive hosts B and CR/s. These str mutants should prove to be useful alternatives to amber mutants for genetic and biochemical studies of bacteriophage T4 and for studies of the E. coli ribosome. It should be possible ot isolate similar mutants in other bacteriophages provided that streptomycin resistant hosts are available.
已经分离出16种噬菌体T4D的条件致死突变体，它们能在大肠杆菌CR63（一种su +链霉素敏感的K12菌株）上生长，但受到CR/s（CR63的链霉素抗性衍生物）的限制。这些突变体被赋予前缀str。其中4个突变体是琥珀型突变，12个似乎是错义突变。12个错义突变体中的11个似乎是“假琥珀型”（即它们受到su -大肠杆菌B菌株的限制，但不受su - K12菌株的限制）；另一个错义突变体不受B或K12的限制。str突变定位于12个不同的基因中。大多数集中在早期基因区域（基因56至基因47）。先前因无法在大肠杆菌B上生长而分离出的58个琥珀型突变体和10个“假琥珀型”突变体，被测试是否受到CR/s的限制。所有琥珀型突变体在CR/s上正常生长，而所有10个“假琥珀型”突变体都受到CR/s的限制。这意味着“假琥珀型”突变体的表型是允许宿主CR63与限制宿主B和CR/s之间核糖体差异的结果。这些str突变体应该被证明是噬菌体T4遗传和生化研究以及大肠杆菌核糖体研究中琥珀型突变体的有用替代物。如果有链霉素抗性宿主，应该有可能在其他噬菌体中分离出类似的突变体。
