Sequence Anaysis Of The Complete Genome Of Porcine Parvovirus YL Strain And Prokaryotic Expression Of VP2

Porcine parvovirus (PPV) can cause reproductive failure in sows. The disease, prevailingin the swine herd, is characterized with mummification, stillbirth, embryonic death and sickpiglets and lead to economic losses to pig breeder in the world. At present, the studies aboutPPV little focused on the whole genome.There were only two complete genome sequencesrecorded in GenBank (Accession no. U44978and NC001718). In order to further analyse themolecular characterizations, the genetic variation and the diagnosis of PPV, PPV YL isolatewas sequenced. Furthermore, the major eptiope domain of porcine parvovirus structuralprotein VP2was expressed by E.coli. From the experiments, the following results wereobtained:1. According to the complete genome of PPV, four pairs of primers which cover thewhole coding region were designed to amplify the whole genome fragments using polymerasechain reaction (PCR) method. The four sequences were spliced and the result showed thatPPV YL strain is composed of4302nucleotides. There is no insertion or deletion in thecoding region. Howere, the genetic mutation exist in the sequence. The sequence had beensubmitted to GeneBank and the accession number is JN860197.2. The main gene of PPV YL strain was compared with other PPV stains isolated fromdomestic and foreign countries. The result of sequence analysis of NS1protein show that PPVYL strain has high homology with two American NADL-2strains and Kresse strain, shares99.4%identity of amino acids with that of the three strains. The sequence alignments of VP2gene and coding protein show that PPV VP2amino acid exhibited99.7%over with otherPPV strains: American Kresse strain and Chinese BQ strain, whose sequences are the samewith the two stains. The result show that the porcine parvovirus is highly conservative. Theanalysis of VP2gene and encoded amino acid differences show that PPV YL strain mighthave the same pathogenicity with Kresse strain. Phylogenetic tree reveal that the PPV YLstrain is closest to Kresse and BQ strain.3. The major eptiope domain of porcine parvovirus structural protein VP2was amplifiedby polymerase chain reaction (PCR) and inserted into the expression plasmid, pET-32a, thenthe recombination was induced by IPTG in Escherichia Coli BL21. SDS-PAGE and Western blotting analysis revealed that the recombinant protein are56Ku. Antigenic activity of therecombinant protein were detected by Western blotting.The results of this study make the foundation for the diagnosis of porcine parvovirusinfection and study the pathogenesis of the disease.