斜纹夜蛾核型多角体病毒Ⅱ型同源重复区的增强子功能分析

Analysis on Enhancer Function of Homologous Regions from Spodoptera litura Nucleopolyhedrovirus Ⅱ

斜纹夜蛾核型多角体病毒Ⅱ型(SpltNPVⅡ)基因组DNA含有7个同源重复区(hr)。采用脂质体介导转染法和瞬时表达实验对7个hr在异源病毒感染的BmN和Sf21细胞中增强异源ie1启动子转录活性的功能进行分析。结果表明,除hr5外,SpltNPVⅡhr均能增强BmNPV ie1启动子的转录活性,其中hr1、hr4和hr7增强效率较高,为对照的30~40倍;7个hr均能显著增强AcMNPV ie1启动子的转录活性,其中hr7增强效率高达1 246倍,其余增强效率在17~538倍之间。另外,SpltNPVⅡhr增强异源ie1启动子转录活性的效率与其所含的正反向重复序列、回文序列以及与复制相关的基序等特征结构的数目存在显著的正相关。

There are 7 homologous regions(hrs) in the genomic DNA of Spodoptera litura nucleopolyhedrovirus Ⅱ(SpltNPVⅡ). The function of 7 hrs to enhance the transcription from heterologous immediate early gene(ie1) promoter in BmN and Sf21 cell lines infected by heterologous viruses was analyzed by liposome-mediated transfection method and transient expression assay. The results indicated that all SpltNPVⅡ hrs except for hr5 could enhance the transcription from heterologous BmNPV ie1 promoter. Among them, hr1, hr4 and hr7 had the highest enhancing efficiency which was 30 to 40 folds higher than that of the control group. Moreover, 7 hrs could also significantly improve the transcription from heterologous AcMNPV ie1 promoter, among which the enhancing efficiency of hr7 was up to 1 246 folds higher and the rest varied from 17 to 538 folds higher than that of the control group. In addition, the enhancing efficiency of SpltNPVⅡ hrs on transcription from heterologous ie1 promoter had a significantly positive correlation with the numbers of direct and inverted repeats, palindromes and replication-related motifs.