猪A组轮状病毒Vp6基因与乳酸菌非抗性表达载体的重组及在大肠杆菌中的表达

Expression of recombinant Vp6 gene of porcine rotavirus A with non-antibiotic Lactobacillus vector in Escherichia coli

以猪A组轮状病毒mRNA为模板,应用反转录聚合酶链式反应(RT-PCR)技术,扩增了1194bp的Vp6基因,通过T-A克隆技术,将PCR产物克隆至克隆载体pGEM-TVector中,构建克隆质粒pGEM-T-Vp6。用SacⅠ和KpnⅠ双酶切pGEM-T-Vp6和以胸苷酸合成酶基因(thymidylate synthase,thyA)为选择压力的非抗生素抗性的穿梭表达载体pW425t,并将纯化的Vp6基因亚克隆至表达载体pW425t中,构建出可以在乳酸菌与大肠杆菌之间穿梭表达的原核表达重组质粒pW425t-Vp6。将pW425t-Vp6转化至thyA基因缺陷型的大肠杆菌感受态E.coliX13中,经生长功能弥补筛选阳性克隆,通过SDS-PAGE分析,可见约44.88kD的融合蛋白。由Western blot分析,表明该蛋白具有与轮状病毒多克隆抗体的反应原性,从而为pW425t-Vp6在乳酸菌受体菌株中表达提供理论基础和实验依据。

The antigenic determinants of Vp6 gene of porcine rotavirus A was amplified from infected MA 104 cell by the reverse transcription-polymerase chain reaction （RT-PCR）, the product of which was a 1194bp cDNA segment. Using T- A cloning technique, the PCR product was cloned into pGEM-T vector. Cloning plasmid pGEM-T-Vp6 and the prokaryotic shuttle expression vector pW425t between E. coli and Lactobacillus , were digested by SacI and KpnI double enzymes, respectively. The purified Vp6 gene was subcloned into the expression vector pW425t. Thus, the recombinant pW425t-Vp6 was constructed, which then was transformed into the competence thyA gene-mutant E. coli X13. Treated lysates of bacterium were loaded directly onto SDS-PAGE, on which approximately 44.88 kD fusion protein was observed. The protein was further analyzed using Western blot, which indicated that the protein was reactive with the antibody of rotavirus A. The results lay foundation for further studies on the Lactobacillus subunit vaccine and DNA vaccine of Vp6 gene for prevention and control of porcine rotavirus.