The Construction and Identification of Recombinant Plasmids of pcDNA3.1(+)-SjPGK of Schistosoma japonicum

Objective To construct the eukaryoctic expression plasmid containing the partial gene of Schistosoma japonicum phosphoglycerate kinase( SjPGK ), and provide a new candidate antigen for preventing schistosomiasis japonica. Methods The gene fragment of SjPGK was amplified and isolated from the total RNA of S.japonicum by Reverse-Transcription Polymerase Chain Reaction ( RT-PCR). The gene fragment was cloned into pMD18-T vector, the positive clones were acquired and identified with restrictive enzymes and PCR amplification. The fragment of SjPGK inserted in pMD18-T was subcloned into the eukaryotic expression plasmid pcDNA3.1. The positive clones were acquired after being identified with restrictive enzymes and PCR amplification and sequence analysis. After being sequenced with DNA auto-sequence analysis instrument,the cDNA sequence of SjPGK was searched for homologue identity with NCBI Blast program. Results The gene encoding SjPGK was obtained and isolated by RT-PCR .The fragment of SjPGK was about 830 bp.The cDNA sequence of the phosphoglycerate kinase was highly homologous between Schistosoma mansoni and Schistosoma japonicum . The identity of nucleotide sequence was 85% and scored 672;The identity of amino sequence was 94% and scored 473. Conclusion The recombinant plasmid of pcDNA3.1-SjPGK was constructed successfully, which provided the basis for constructing nucleic acid vaccine of SjPGK.