China Animal Husbandry and Veterinary Medicine ›› 2020, Vol. 47 ›› Issue (5): 1318-1325.doi: 10.16431/j.cnki.1671-7236.2020.05.004

• Biotechnology • Previous Articles     Next Articles

Prokaryotic Expression of Canine Coronavirus N Protein and Preparation of Its Polyclonal Antibody

ZHOU Yahua, YIN Juanbin, LIU Le, YIN Xiangping, LI Yanmin, ZHANG Zhidong   

  1. State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China
  • Online:2020-05-20 Published:2020-05-18

Abstract: The purpose of this study was to clone the N gene of canine coronavirus(CCV),express the N protein in vitro,and prepare a polyclonal antibody against this protein for the diagnosis of CCV and its antigen detection.Referring to the N gene sequence of CCV in GenBank (accession No.:KY063618.2) and the N gene of CCV epidemic strain was selected,and the recombinant expression plasmid pET-B2M-N was constructed by codon optimization and gene synthesis.Finally,an effective gene was selected to construct the recombinant plasmid,which transformed into E.coli DH5α constructer.After sequencing,positive clones were transformed into E.coli BL21 (DE3) strain and induced by IPTG.Finally,IPTG concentration of 0.5 mmol/L was used to induce at 30 ℃.The results showed that the recombinant plasmid pET-B2M-N containing canine coronavirus N gene was successfully constructed.After optimizing the induction conditions,the recombinant protein with a size of about 49 ku was successfully expressed.The recombinant protein was mixed with Freund’s adjuvant to immunize Japanese White rabbits G767 and G768 for several times,and the G768 antibody titer was up to 1:512 000 assayed by indirect ELISA.The antibody could be purified to 10 mg/mL.The charactered of polyclonal antibodies detected by ELISA,Western blotting and immunofluorescence,indicating that the expressed recombinant N protein had good immunogenicity and reactogenicity.This study provides a basis for the detection of canine coronavirus antigen and antibodies and the establishment of target CCV diagnostic kit.

Key words: canine coronavirus(CCV); N gene; prokaryotic expression; polyclonal antibody

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