ABSTRACT Interferon-induced transmembrane (IFITM) proteins as host restriction factors are known to inhibit the replication of several viruses. In this study, transient IFITM expression vectors were used to investigate whether IFITMs inhibit feline foamy viral (FFV) replication and which step of viral replication is inhibited. In our studies, viral production was significantly reduced when cells were infected with FFV at almost same times such as −3, 0, or 3 h post-transfection with IFITM vector. However viral production was not reduced even though cells were infected with FFV at 3 or 6 days post-transfection when production of IFITM proteins was maximized. Considering that IFITM expression was maximized at 3 days post-transfection, the stage of viral replication inhibited by IFITM appears to be the late step of viral replication. Moreover, the viral Gag proteins detected in the virus-infected cell lysates were proportionally correlated with viral titer of the culture supernatants. Therefore, it is likely that IFITMs can restrict production of FFV at the late step of viral replication.

中文翻译：

---

IFITM蛋白抑制猫泡沫病毒复制的后期

摘要 作为宿主限制因子的干扰素诱导跨膜 (IFITM) 蛋白已知可抑制多种病毒的复制。在这项研究中，瞬时 IFITM 表达载体用于研究 IFITMs 是否抑制猫泡沫病毒 (FFV) 复制以及病毒复制的哪个步骤被抑制。在我们的研究中，当细胞在几乎相同的时间（例如在用 IFITM 载体转染后 -3、0 或 3 小时）用 FFV 感染时，病毒产量显着降低。然而，当 IFITM 蛋白的产量最大化时，即使细胞在转染后 3 或 6 天被 FFV 感染，病毒产量也没有减少。考虑到 IFITM 表达在转染后 3 天达到最大，IFITM 抑制病毒复制的阶段似乎是病毒复制的后期。而且，在病毒感染的细胞裂解物中检测到的病毒 Gag 蛋白与培养物上清液的病毒滴度成正比。因此，IFITMs 可能会在病毒复制的后期限制 FFV 的产生。