转录是病毒基因表达的第一步，也是基因表达调节的主要步骤。在进化过程中病毒形成非常有效的调节机制来利用宿主系统，获得病毒基因的表达。尽管对硫化叶菌RNA聚合酶结构的研究已经取得进展，但目前还不清楚感染过程中硫化叶菌病毒基因转录的调节机制。本项目以一株硫化叶菌H5-2及其病毒STSV2作为研究对象，结合理论分析和多种实验方法，分析感染过程中STSV2基因转录的时序变化以及这种变化与基因分布和启动子结构的关系。进一步分离硫化叶菌RNA聚合酶蛋白复合物中病毒编码蛋白，研究感染过程中这些蛋白对宿主RNA聚合酶特异性调节和对病毒和宿主基因时序转录的影响，阐明STSV2基因时序表达与启动子结构和宿主RNA聚合酶特异性调节的关系，揭示感染过程中STSV2病毒基因时序转录的调节机制。项目研究也将有助于揭示硫化叶菌病毒在宿主细胞中基因表达的相关调节过程，对研究古生菌与病毒的关系、起源、进化和多样性提供参考。

Transcription is the first step and primary regulatory determinant of viral gene expression. Viruses have evolved highly effective mechanisms to exploit their host for the expression of viral genes. Although progresses have been made on the structure elucidation of RNA polymerases from Sulfolobus, our understanding of gene expression regulation strategies utilized by viruses is still relatively limited. In this work, a Sulfolobus spindle-shaped virus STSV2 and its host Sulfolobus strain H5-2 isolated from Tengchong hot springs will be applied to study the temporal regulation of viral gene transcription and the relationship of this regulation with gene distribution and gene promoter structures in the genome of virus STSV2 by combined therotical analysis and several experimental techniques. Virus-encoded proteins that bind to RNA polymerase complex of the Sulfolobus strain H5-2 will be purified and identified, and the regulaiton of host RNA polymerase activity by the viral proteins and the effects of these proteins on the temperal transcription of viral genes during infection will be subsquently investigated. Based on these reslults, the relationship of temporal gene transcription of virus STSV2 with promoter structure and functional modification of host RNA polymerase specificity will be explored, and the mechanism of temporal regulation of STSV2 gene transcription will also be further elucidated. This study will contribute to uncover the basal regulaiton processes of viral gene expression in Sulfolobus and provide a basis for further research of the interaction, origin, evolution and diveristy of archaea and their viruses.