Tat蛋白对马传染性贫血病毒长末端重复序列启动子活性的影响

将来源于马传染性贫血病毒(EIAV)强毒株第25代和第118代病毒的LTR,白细胞弱毒(EIAV-DLA)的LTR,以及TAR起始碱基和/或poly(A)附加位点发生突变的驴胎皮肤细胞弱毒(EIAV-FDD)的LTR分别克隆到pCAT3-Basic质粒中,获得了6个重组质粒pCAT-25、pCAT-118、pCAT-FD、pCAT-G219A、pCAT-A294C和pCAT-G219A-A294C。同时用pcDNA3.1(+)构建了EIAV反式激活蛋白(Tat)基因的重组真核表达质粒pcTM7-D。将pcTM7-D分别与含有不同LTR的重组质粒共转染驴胎皮肤细胞,考察Tat对LTR启动子活性的增强作用。结果表明,在皮肤细胞中Tat蛋白可以特异性增强来源于皮肤细胞弱毒疫苗株LTR的启动子活性,而对白细胞源的LTR无明显增强作用;TAR起始位点和poly(A)的单碱基突变和联合突变对Tat的反式激活作用并无明显影响。

Effect of Tat protein expressed in fetal donkey dermal cells on activity of promoter of LTR from equine infectious anemia virus

The LTRs(long terminal repeat) from passage 25 of equine infectious anemia virus(EIAV),passage 118 of EIAV,donkey leukocyte attenuated EIAV(EIAV-DLA),and fetal donkey dermal cell attenuated EIAV(EIAV-FDD) with mutations in the initiation bases and/or the appending site of poly(A) were cloned into pCAT3-basic,respectively,and recombinant plasmids pCAT-25,pCAT-118,pCAT-FD,pCAT-G219A,pCAT-A294C and pCAT-G219A-A 294C were constructed.Then,the recombinant plasmid expressing Tat protein pcTM7-D was constructed by inserting Tat protein gene into pcDNA3.1(+).The plasmid pcTM7-D was co-transfected with one of the 6 plasmids with different LTR into fetal donkey dermal cell mediated by LipofectamineTM 2000 regent,to observe effect of Tat protein on LTR promoter.Results showed that the EIAV Tat protein expressed in the fetal donkey dermal cells can specifically increase the activity of the LTR promoter from EIAV-FDD but not EIAV-DLA,and the mutations of TAR or/and poly(A) did not affect the Tat-induced activity.