Issinger O G, Hausmann R
J Virol. 1973 Apr;11(4):465-72. doi: 10.1128/JVI.11.4.465-472.1973.
During nonpermissive infection by a T7 amber mutant in gene 1 (phage RNA polymerase-deficient), synthesis of the products of the phage genes 3 (endonuclease), 3, 5 (lysozyme), 5 (DNA polymerase), and 17 (serum blocking power) was shown to occur at about half the rate as during wild-type infection. This relatively high rate of expression of "late" genes (transcribed normally by the phage RNA polymerase) seems to be a general feature of all T7 mutants in gene 1 from our collection. In contrast, T3 gene 1 mutants and a T7 gene 1 mutant from another collection showed late protein synthesis at very reduced rates. Synthesis of the gene 3 endonuclease by T7 gene 1 mutants was very sensitive to the addition of rifampin 2 min after infection, conditions under which there was very little inhibition during wild-type infection. This supports the notion that late gene expression during nonpermissive infection by gene 1 mutants is dependent on the transcription of the T7 genome by the host RNA polymerase. In contrast to T3 gene 1 mutants, the T7 gene 1 mutants of our collection directed the synthesis of phage DNA during nonpermissive infection. This DNA accumulated as a material sedimenting faster than mature T7 DNA.
在由基因1中的T7琥珀突变体（噬菌体RNA聚合酶缺陷型）进行的非允许感染期间，噬菌体基因3（核酸内切酶）、3、5（溶菌酶）、5（DNA聚合酶）和17（血清阻断力）的产物合成速率约为野生型感染期间的一半。“晚期”基因（通常由噬菌体RNA聚合酶转录）的这种相对较高的表达速率似乎是我们收集的所有基因1中的T7突变体的一个普遍特征。相比之下，来自另一个收集品系的T3基因1突变体和一个T7基因1突变体显示晚期蛋白质合成速率非常低。T7基因1突变体对感染后2分钟添加利福平非常敏感，在这种条件下野生型感染期间几乎没有抑制作用。这支持了这样一种观点，即基因1突变体在非允许感染期间的晚期基因表达依赖于宿主RNA聚合酶对T7基因组的转录。与T3基因1突变体不同，我们收集的T7基因1突变体在非允许感染期间指导噬菌体DNA的合成。这种DNA以一种沉降速度比成熟T7 DNA更快的物质形式积累。
