DNA TOPOMERASE 1 ACTIVITY IN RETROVIRUSES

拓扑异构酶是一种改变DNA和DNA的拓扑状态的酶 已被证明与DNA复制和转录有关。 由于逆转录病毒的复制、整合和表达过程 可能需要在集成的或 未整合的前病毒，我们已经开始确定拓扑异构酶是否起作用 在逆转录病毒的生长或感染中起关键作用，或者如果拓扑异构酶 可能是控制逆转录病毒感染的目标。 我们之前描述了一种新的拓扑异构酶I(Topo I)活性 与各种逆转录病毒和慢病毒颗粒有关，并显示 特定的Topo I抑制剂喜树碱(CPT)可以阻断HIV H9细胞在组织培养中的感染。运用健脾成灶 病毒(SFFV)诱导的脾肿大作为体内模型，我们已经证明 CPT与病毒共注射可阻断SFFV诱导的疾病 变成易受感染的小鼠。确定CPT对慢性阻塞性肺疾病的影响能力 通过感染细胞产生病毒，我们处理了CF2Th(狗胸腺)细胞 用CPT生产马传染性贫血病毒。连续曝光 低水平的药物对病毒的产生有85%-92%的抑制作用 Ttion，通过释放到培养基中的RT测量，以及类似的 免疫荧光法和免疫荧光法降低病毒蛋白产量的水平 放射免疫沉淀分析。

Topoisomerases are enzymes which modify the topological state of DNA and have been shown to be involved in DNA replication and transcription. Since the process of retroviral replication, integration and expression are likely to require topological changes in either the integrated or unintegrated provirus, we have begun to determine if topoisomerases play a critical role in retrovirus growth or infection, or if topoisomerases might be a target for the control of retroviral infections. We had previously described a novel topoisomerase I (topo I) activity associated with various retrovirus and lentivirus particles, and showed that the specific topo I inhibitor, camptothecin (CPT), could block HIV infection of H9 cells in tissue culture. Using spleen focus-forming virus (SFFV) induction of splenomegaly as an in vivo model, we have shown that CPT can block SFFV-induced diseases when coinjected with the virus into susceptible mice. To determine the ability of CPT to affect chronic virus production by infected cells, we treated CF2Th (dog thymus) cells producing equine infectious anemia virus with CPT. Continuous exposure to low levels of the drug resulted in 85-92% inhibition of virus produc- tion, as measured by RT released into the culture media, and similar levels of reduction in viral protein production by immunofluorescence and radioimmunoprecipitation analysis.