禽腺病毒QU株一个复制非必需区的鉴定

Identification of a Non-essential Region for Replication of Fowl Adenovirus QU Strain

禽腺病毒QU弱毒株属于鸭腺病毒1型病毒,可作为潜在的重组疫苗载体。为确定QU株的复制非必需区,参照鸭腺病毒1型病毒基因组右侧E4区附近序列设计引物,扩增QU株基因组的一段3.4kb片段,插入来自pEGFP-C1质粒的增强型绿色荧光蛋白(EGFP)基因表达盒片段,构建了含EGFP基因的重组质粒pADGFP。采用脂质体介导法,将重组质粒pADGFP与QU株共转染CEF细胞,用96孔板稀释法筛选纯化表达绿色荧光蛋白的重组QU病毒株rQUGFP。该重组毒的生长曲线与亲本毒一致,连续传代后病毒滴度稳定。结果表明,QU株基因组右侧E4区附近一段包括ORF1、ORF8和ORF9三个开放阅读框的区域为病毒的复制非必需区,且插入的EGFP基因可以稳定表达。为进一步以禽腺病毒QU株为载体构建重组疫苗的研究打下基础。

The avirulent QU strain of fowl adenovirus, a member of duck adenovirus type 1, could be a potential vector in recombinant vaccine development. To identify a non-essential region for replication of QU virus, a 3.4 kb fragment near the E4 region of QU virus genome was amplified by PCR to construct a plasmid pADGFP, in which ORF1, ORF8 and ORF9 was replaced with a system expressing enhanced green fluorescence protein. Further, a recombinant virus rQUGFP was constructed by homologous recombination after pADGFP and QU virus were co-transfected into chick embryo fibroblast. The one step growth curve of the rQUGFP was found to be identical with that of parent QU virus and the TCIDs0 titers of different generation recombinants maintained stable. These findings suggest that the region including ORF1, ORF8 and ORF9 of QU virus genome is dispensable for virus replication, and the foreign gene inserted into virus genome can be efficiently and stably expressed. The work lays the foundation for further studies of developing this virus as a vector of recombinant vaccine.