Hercules K, Sauerbier W
J Virol. 1974 Aug;14(2):341-8. doi: 10.1128/JVI.14.2.341-348.1974.
Sensitivities of the expression of early genes of phage T4 to UV light were determined at various stages of intracellular development of T4 wild type, a DNA-negative mutant (T4 DO), and T4 tsG1, (a mutant that exhibits delayed expression of some T4 early genes). Whereas the sensitivities of some genes in the T4 wild type and T4 DO remain constant, genes 43 and 45 exhibit greatly reduced sensitivities several minutes after the onset of phage development. Since UV sensitivities are a measure of the distance of a gene from its promotor, these observations indicate a switch from distal, "immediate early" promotors to proximal, "delayed early" promotors for genes 43 and 45. In the tsG1 mutant this decrease in UV sensitivities of genes 43 and 45 does not occur at 42 C, suggesting that at high temperature this mutant does not utilize the delayed early promotors.
在T4野生型、DNA阴性突变体（T4 DO）和T4 tsG1（一种表现出某些T4早期基因表达延迟的突变体）细胞内发育的各个阶段，测定了噬菌体T4早期基因表达对紫外线的敏感性。虽然T4野生型和T4 DO中某些基因的敏感性保持不变，但在噬菌体发育开始几分钟后，基因43和45的敏感性大大降低。由于紫外线敏感性是一个基因与其启动子距离的衡量指标，这些观察结果表明基因43和45从远端的“立即早期”启动子切换到了近端的“延迟早期”启动子。在tsG1突变体中，基因43和45的紫外线敏感性在42℃时不会降低，这表明在高温下该突变体不使用延迟早期启动子。
