The Construction Of CSFV Shimen Strain With A Segmented Genome

Classical swine fever (CSF) caused by virulent strains of classical swine fevervirus (CSFV) is a hemorrhagic disease of pigs. It often causes major losses in stockfarming characterized by disseminated intravascular coagulation, thrombocyt openiaand immunosuppression. Recently, many researchers have foused on the developmentof novel vaccine and diagnostic methods. However, the molecular pathogenesis ofCSFV is still not well understood.Classical swine fever is a highly contagious and sometimes fatal viral disease inpigs. As a member of the pestivirus genus within the family Flaviviridae, CSFV has apositive，single—stranded RNA genome．Its genome is approximately12.3kb inlength and comprises a long open reading frame flanked (ORF)by5’ and3’ untranslated regions(UTRs)． The ORF is translated to a primarypolyprotein subsequently processed into12matural proteins by cellular and viralproteases, including8nonstructural proteins (NSPs) and4structural proteins(SPs).There is two typical CSFV strains in China, shimen isolate and C-strain. Theformer were collected in1945, containing high immunogenicity while the latter is hogcholera lapinized virus (HCLV), the attenuated characteristic and thewell-immunogenicity can inhert to progeny constantly. Based on the safety andefficiency, the HCLV is the advantage for immuning pig stock. However, it isdifficult to differate HCLV from the wild type strains in clinlic diagnosis, and thus,EU forbid this strategy.The reverse genetics has significant influence in research of orthology virus.RNA in vitro transcription is the backbone of the reverse genetics. Traditionally,reseachers always use RNA as the transfection resource, which is from cDNA.The instability and inhomogeneity of RNA is the nut in the program, as well as virus RNAexpressed in higher-than-usual quantities of virus RNA.In this study, we reconstructd the cDNA of shimen strain through joining theHDV to the3’terminal of CSFV genome in order to in vivo transcription andtranslation of CSFV and improve the quantity of the virus recover.In addition, we try to construct genome-segemented CSFV, which is helpful todifferate the wild type CSFV from vaccine viruses in genomic level. Thus, this studymight provide a important clue for construct a genome-segmented CSFV vaccine. Atthe same time, this study is also basis on identification of the package signal of CSFV.