杆状病毒早期基因表达和晚期基因表达分别依赖宿主RNA聚合酶和其自身编码的RNA聚合酶。其晚期基因转录起始和调控机制尚未明了。IE1是一个极早期表达的多功能病毒蛋白，是病毒早期基因激活和DNA复制必需因子，也是已知的晚期表达因子之一。然而其在晚期基因表达中的作用尚未阐明。本项目拟在前期发现IE1可能直接参与晚期基因表达激活的基础上通过对苜蓿银纹夜蛾核多角体病毒(AcMNPV) RNA基因缺失突变体和ie1相关克隆质粒转染细胞培养的病毒晚期基因转录产物及其转录起始位点的测定验证IE1对病毒晚期基因的激活作用；识别IE1激活晚期基因表达的相关功能域或结构域；筛查和鉴定IE1的互作蛋白并分析IE1与其它蛋白的相互作用对晚期基因表达的影响。通过这些研究工作揭示IE1在杆状病毒晚期基因表达中的作用及作用机制。本项目研究工作的完成将推进对杆状病毒晚期基因表达机制的阐释，为杆状病毒的改良和利用提供理论依据

Early gene expression and late gene expression of baculoviruses rely on the host RNA polymerase II and a virus-encoded RNA polymerase respectively. The mechanism for initiation of late gene transcription has not been elucidated. IE1 is a multiple functional viral protein expressed in immediate early stage of infection. It is required for activation of viral early gene expression and DNA replication, and is one of the identified late expression factors. The role it plays in late virus late gene expression is not clear yet. In a previous study, we found that Autographa californica multiple nucleopolyhedrovirus IE1 is possibly involved in late gene expression directly. In this project, we plan to verify the role of IE1 in activation of virus late gene transcription by detection of the transcripts of some late virus genes in cell culture transfected with individual ie1 transient expression plasmids or by AcMNPV recombinants with the genes of the subunits of RNA polymerase knocked out, and identification of the transcription start site. Subsequently, we are going to identify the domains in IE1 associated with activation of late gene transcription. In further, experiments will be performed to identify interaction between IE1 and additional viral proteins or host insect proteins, and investigate effects of interaction between IE1 and addition proteins on late gene expression. The project intends to find out the role of AcMNPV IE1 in late gene expression. Completion of the project would contribute to reveal the mechanism of late gene expression initiation and regulation of baculoviruses and provide theoretical bases for improvement of the viruses by genetic engineering for application.