Trimble R B, Galivan J, Maley F
Proc Natl Acad Sci U S A. 1972 Jul;69(7):1659-63. doi: 10.1073/pnas.69.7.1659.
The kinetic order of synthesis of deoxycytidylate deaminase (EC 3.5.4.12), deoxycytidylate hydroxymethylase (EC 2.1.2.b), dihydrofolate reductase (EC 1.5.1.3), 5-hydroxymethyldeoxycytidylate kinase (EC 2.7.4.4), and thymidylate synthetase (EC 2.1.1.b) after infection of Escherichia coli with T2r(+) bacteriophage was found not to correlate with their order of synthesis in an in vitro protein-synthesizing preparation. The in vivo and in vitro synthesis of enzyme-specific messenger RNA measured in the protein-synthesizing preparation preceded each enzyme by about 1 min. Through the use of sheared DNA, it was shown that the thymidylate synthetase gene was most susceptible to a loss in template activity, which suggests that this gene is further removed from its promoter than the other genes are from theirs. With a DNA segment of 2.5 x 10(5) daltons, the synthesis of dihydrofolate reductase alone was obtained, but at a much reduced rate. Translation of the RNA from phage-infected cells treated with chloramphenicol yielded amounts of dihydrofolate reductase and deoxycytidylate hydroxymethylase activities similar to those obtained with RNA from untreated infected cells. These results suggest that the chloramphenicol RNA, which consists primarily of immediate-early RNA, may contain most, if not all, of the information required for the synthesis of phage dihydrofolate reductase and deoxycytidylate hydroxymethylase.
用T2r(+)噬菌体感染大肠杆菌后，发现脱氧胞苷酸脱氨酶（EC 3.5.4.12）、脱氧胞苷酸羟甲基化酶（EC 2.1.2.b）、二氢叶酸还原酶（EC 1.5.1.3）、5-羟甲基脱氧胞苷酸激酶（EC 2.7.4.4）和胸苷酸合成酶（EC 2.1.1.b）的合成动力学顺序与它们在体外蛋白质合成制剂中的合成顺序不相关。在蛋白质合成制剂中测得的酶特异性信使RNA的体内和体外合成比每种酶提前约1分钟。通过使用剪切的DNA表明，胸苷酸合成酶基因最容易丧失模板活性，这表明该基因与其启动子的距离比其他基因与其启动子的距离更远。用2.5×10(5)道尔顿的DNA片段，仅获得了二氢叶酸还原酶的合成，但速率大大降低。用氯霉素处理的噬菌体感染细胞的RNA翻译产生的二氢叶酸还原酶和脱氧胞苷酸羟甲基化酶活性的量与未处理的感染细胞的RNA产生的量相似。这些结果表明，主要由早期RNA组成的氯霉素RNA可能包含噬菌体二氢叶酸还原酶和脱氧胞苷酸羟甲基化酶合成所需的大部分（如果不是全部）信息。
