CLONE AND SEQUENCE COMPLETE E2 GENE OF CLASSICAL SWINE FEVER VIRUS FROM SEVERAL FARMS IN THE SOUTH VIETNAM

Abstract

Classical swine fever is an old and dangerous disease that causes significant economic losses to the swine industry worldwide. E2 protein-coding gene sequencing is an essential basis for assessing and comparing the genetic diversity of CSFV and developing a vaccine against CSFV. This study was conducted to create E. coli cells carrying plasmids containing the full-length E2 gene sequences. Twenty-one CSFV-positive samples were collected that were transformed into E. coli DH5α cells. The plasmids were then purified and sequenced to evaluate the effectiveness of the cloning method. The results showed that the research has successfully created 21 strains of E. coli bacteria carrying the complete E2 gene. These sequences were highly similar (87.94 – 98.84%) compared with the 100 sequences having the highest similarity on NCBI. Besides, 19 sequences had very high similarity with strains belonging to subgroup 2.1c (95.00 - 96.34%) and two sequences with subgroup 2.2 (92.05 - 93.03%). This study is the basis for applying the E. coli cloning technique carrying the E2 gene in stable genetic analysis of CSFV, as well as the basis for the subsequent generation of recombinant E2 proteins for developing an E2-subunit vaccine against CSFV.