Wright C F, Oswald B W, Dellis S
Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
J Biol Chem. 2001 Nov 2;276(44):40680-6. doi: 10.1074/jbc.M102399200. Epub 2001 Aug 23.
Vaccinia virus gene expression is temporally regulated, and three gene classes have been identified: early, intermediate, and late. Several virus-encoded proteins and an activity designated VLTF-X are required for maximum transcription in vitro of a template containing a late promoter. VLTF-X is present in both cytoplasmic and nuclear extracts prepared from uninfected mammalian cells and co-purifies with a late promoter DNA-binding activity. Here, extensive purification of VLTF-X has revealed that heterogeneous nuclear ribonucleoproteins A2/B1 and RBM3 co-purified with in vitro late transcription stimulation. Overexpression and purification of these proteins from Escherichia coli demonstrated that they both complemented for VLTF-X activity in in vitro transcription reactions. These studies identify two host cell factors potentially contributing to poxvirus replication in vivo.
痘苗病毒基因表达受时间调控，已鉴定出三类基因：早期、中期和晚期。含有晚期启动子的模板在体外进行最大转录需要几种病毒编码蛋白和一种名为VLTF-X的活性物质。VLTF-X存在于从未感染的哺乳动物细胞制备的细胞质和核提取物中，并与晚期启动子DNA结合活性共纯化。在这里，对VLTF-X的广泛纯化表明，异质性核核糖核蛋白A2/B1和RBM3与体外晚期转录刺激共纯化。从大肠杆菌中对这些蛋白进行过表达和纯化表明，它们在体外转录反应中均能补充VLTF-X的活性。这些研究确定了两种可能在体内促进痘病毒复制的宿主细胞因子。
