Study on the DNA replication of herpes simplex virus

实验结果如下：1）表鬼臼毒素VP-16 - 213和喜树碱分别干扰哺乳动物DNA拓扑异构酶II和I的功能。这两种抑制剂都能强烈抑制单纯疱疹病毒的生长。结果表明，细胞DNA拓扑异构酶II和I参与了HSV的复制，前者主要在病毒DNA复制中起作用，而后者主要在转录水平起作用。2）已分离到抗蚜蝇菌素或抗膦酰乙酸的HSV突变体。Aph ^r突变的物理图谱界限包含在HSV DNA聚合酶基因座内的1.1 Kbp区域内。结果表明，Aph ^r突变体聚合酶在DNA聚合酶的保守区由一个甲状腺素氨基酸替换为一个组氨酸氨基酸，DNA推测该区域可能形成一个含有底物PPi和蚜虫素结合位点的结构域。在不影响HSV诱导的早期蛋白合成的浓度下抑制HSV DNA合成。需要进一步的研究来确定这种化合物的靶点。

The results of our experiments are summarized as follows.1) The epipodophyllotoxin VP-16-213 and camptothecin have been shown to interfer with the functions of mammalian DNA topoisomerase II and I, respectively. Both inhibitors strongly suppressed the growth of herpes simplex virus. From our experiments using the two inhibitors, if was suggested that celluler DNA topoisomerase II and I are involved in the HSV replication; The former enzyme mainly plays a role in the viral DNA replication but the latter seems to primarily act at the level of transcription.2) Aphidicolin-resistant or phosphonoacetic acid-resistant mutants of HSV have been isolated and characterized. The physical map limits for the Aph^r mutation were contained in a 1.1 Kbp region within the HSV DNA polymerase locus. It was shown that the Aph^r mutant polymerase had an amino acid substitution from a thyrosin to a histidine in the wellconserved region of the dna polymerase, DNA suggested that this region may form a domain that contains the binding-sites for substrates, PPi and aphidicolin.3) We found that citrusinine-i, a new acridone alkaloid isolated from the root bark of citrus plant, inhibited HSV DNA synthesis at the concertrations that did not affect the synthesis of HSV-induced early proteins. Further studies will be required to determine the target of this compound.