Heere L J, Karam J D
J Virol. 1975 Oct;16(4):974-81. doi: 10.1128/JVI.16.4.974-981.1975.
Temperature-sensitive (ts) mutants of the T4 phage rII gene were islated and used in temperature shift experiments that revelaed two different expressions for the normal rII (rII+) gene function in vivo: (i) an early expression (0 to 12 min postinfection at 30 C) that prevents restriction of T4 growth in Escherichia coli hosts lysogenic for gamma phage, and (ii) a later expression (12 to 18 min postinfection at 30 C) that results in restriction of T4 growth when the phage DNA ligase (gene 30) is missing. The earlier expression appeared to coincide with the period of synthesis of the protein product of the T4 rIIA cistron, whereas the later expression occurred after rIIA protein synthesis had stopped. The synthesis of the protein product of the rIIB cistron continues for several minutes after rIIA protein synthesis ceases (O'Farrell and Gold, 1973). The two rII+ gene expressions might require different molar ratios of the rIIA and rIIB proteins. It is possible that the separate expressions of rII+ gene function are manifestations of different associations between the two rII proteins and other T4-induced proteins that are synthesized or activated at different times after phage infection.
T4噬菌体rII基因的温度敏感（ts）突变体被分离出来，并用于温度转换实验，这些实验揭示了正常rII（rII+）基因功能在体内的两种不同表达：（i）早期表达（在30℃下感染后0至12分钟），可防止T4在对γ噬菌体溶原的大肠杆菌宿主中生长受到限制；（ii）后期表达（在30℃下感染后12至18分钟），当噬菌体DNA连接酶（基因30）缺失时，会导致T4生长受到限制。早期表达似乎与T4 rIIA顺反子蛋白质产物的合成时期一致，而后期表达发生在rIIA蛋白质合成停止之后。rIIB顺反子蛋白质产物的合成在rIIA蛋白质合成停止后仍会持续几分钟（奥法雷尔和戈德，1973年）。rII+基因的两种表达可能需要rIIA和rIIB蛋白质的不同摩尔比。rII+基因功能的单独表达有可能是两种rII蛋白质与噬菌体感染后不同时间合成或激活的其他T4诱导蛋白质之间不同关联的表现。
