插入单个loxP位点的伪狂犬病病毒上海株TK基因缺失株的构建  

Construction of TK Gene-deleted PRV SH StrainContaining a Single LoxP Site

作　　者：王敏秀[1] 苏鑫铭[1] 于春梅[1] 曹瑞兵[1] 陈溥言[1] 

机构地区：[1]南京农业大学农业部动物疫病诊断与免疫重点开放实验室,南京210095

出　　处：《中国生物工程杂志》2006年第10期36-40,共5页China Biotechnology

摘　　要：根据GenBank已发表的pEGFP-C1序列,设计并合成两对引物,PCR扩增出两端各含一loxP位点的GFP表达盒GFP-loxP。克隆于转移载体pSKLR获得pSKLR-GFP-loxP。基于同源重组原理,pSKLR-GFP-loxP与PRVSH株基因组DNA共转染293T细胞,在BrdU的筛选压力下,利用蚀斑法在TK-143细胞上筛选出表达GFP的TK基因缺失的重组毒株rPRV1。将表达Cre酶的质粒载体pPOG231与rPRV1基因组DNA共转染293T细胞,在Cre酶的作用下去除GFP表达盒以及一个loxP位点,筛选得到含单个loxP位点的重组病毒株rPRV2。PCR扩增证实所获得的重组病毒TK缺失270bp,只有一个34bp的loxP位点,并且能在RK-13细胞上稳定传代。LD50试验表明rPrV2的毒力下降。Pseudorabies virus （PRV） is a swine herpesvirus of the Alphaherpesvirinae subfamily and a pathogen of swine resulting in devastating disease and economic losses worldwide. Cre/loxP site-specific system has the character of site specific, time specific, tissue specific and high efficiency in recombination, which makes this system universal in vivo and in vitro recombination of bacteria, fungus, plants, insects and mammals. A recombinant PRV which contain a loxP site in TK locus by using Cre/LoxP recombinant system was construsted. A pair of primers were synthesized according to the pEGFP-C1 sequence published on GenBank, and were used to amplify the EGFP gene expression cassette with two loxP sites flanking each side. This target gene was cloned into pSKLR, the resulting transfer vector pSKLR-GFP-loxP was then cotransfected into 293T cells with PRV SH strain genomic DNA. The recombinant virus rPRV1 was selected and purified in TK-143 cells by choosing fluorescent expressing plaques. Cre expression vector pOG231 was cotransfected into 293T cells with rPRV1 genomic DNA. The second recombinant virus rPRV2 was obtained, which contains only one loxP site in TK locus. Sequencing results of rPRV2 TK gene indicated that 34bp loxP site was inserted into rPRV2 genome and there were 270bp deletion in TK gene. PCR amplifying different generations of rPRV2 TK gene showed that the mutant was stable when passages in RK-13 cells. TCIDs0 assay indicated that rPRV2 grows well on RK-13 cells. The LDs0 test results on BALB/C mice suggested that the virulence of rPRV2 was reduced. As a conclusion, the report gene GFP expression cassette was removed successfully from rPRV1 genome and only one LoxP site was leaved in rPRV2 genome by using Cre/LoxP recombinant system.

关 键 词：伪狂犬病痛毒 TK基因 CRE LOXP GFP重组病毒 

分 类 号：Q819[生物学—生物工程]