| PRRSV is one of causative agent of reproductive disorder, it has make humorous economic losses. GP5 protein is one of the major structural protein and it can induce neutralization antibody to PRRSV, so that it can be used to develop genetic engineering vaccine. A pair of specific primers to amplify complete GP5 gene of PRRSV S1 was designed, according to the sequence of American standard strain of ATCC VR-2332. Primers contain Kpnl and Xhol restriction enzyme at the 5' end respectively. The total RNA of Marc-145 cell infected by virulent strain S1 extracted with TRIZOL reagent, and cDNA was obtained by M-MLV reverse, and was used the template in PCR. The result of RT-PCR showed that the length of fragment of PCR was similar to what we expected. The purified PCR fragment for amplifying GP5 gene of PRRSV was digested by two restriction enzymes Kpnl and Xhol. and purified with gel extracted Kit. And it was ligased into shuttle vector pShuttle-CMV plasmid digested with the same enzyme by T4 DNA ligase. The recombinanted plasmid pShuttle-CMV-GP5 was identified with the Kpnl and Xhol digestion, PCR, and sequencing. The result analyzed by biosoft showed that the GP5 gene was cloned into pShuttle-CMV in correct opening frame (ORF). Constructed pShuttle-CMV-GP5 was purified by DNA purification Kit and linearied by restriction enzyme Pmel or EcoRl. The mixture of linearied pShuttle-CMV-GP5 and adenovirus backbone vector pAdEasy-1 were co-transformed into E-coli strain BJ5183 by electroporation to obtain homologous recombination. The transformed E-coli BJ5183 was put on LB plate with Kanamycin. After 24 hours, the smaller clones on the plate were picked up and inoculated into LB culture with kanamycin and shaked overnight. The extracted plasmid about 40kb length was identified by restriction enzyme Pad and electrophoresed. Consequently, correct recombinanted adenoviral plasmid have two kinds of electrophoresis modes of 35kb and 3kb, 35kb and 4.5kb respectively. To obtain the linearied recombinanted adenoviral plasmid for transfection, the plasmid was extracted in large scale by DNA purification Kit, linearied by Pad restrictionenzyme, extracted by phenol: choloroform and precipitated by sterile ethanol. Then the plasmid DNA was transfected into HEK293-A cell with TransFast Transfection Reagent Kit. In that HEK293-A cell was integrated with El and E3 gene of adenovirus, the recombinanted adenoviral plasmid pAd-GP5 can be encapsided a complete virus particle in HEK292-A cell. Recombinanted adenovirus was purified by plaque forming unit (pfu), and phaged by 3 times in 293-A cell line. The expression of GP5 of PRRSV was identified by RT-PCR, indirect immunofluorescent assay (IFA). The virus liter is 104.33 TCID50/ 1.0ml, then the virus was passaged 3 times in HEK293-A and the titer is still stable. We can concluded that the expression of GP5 of PRRSV in recombinant adenovirus is stable and this may be play a significant role in develop recombinant adenovirus vaccine of PRRS. |
