Cloning and Codon-optimized Expression of Structural Protein Hypervariable Region of VP۲ from Infectious Bursal Disease Virus

Infectious bursal disease virus (IBDV) is the causative agent of Gumboro disease, an infectious disease of global economic importance in poultry. Structural protein VP۲ of IBDV is the most frequently studied protein due to its significant roles in virus attachment, protective immunity, and serotype specificity. The objective of the present study was to improve the expression of hypervariable region of VP۲ protein (hvVP۲) in Escherichia  coli (E.coli). The results showed that the hvVP۲ was expressed in very low amount in E.coli. But, codon optimized hvVP۲ protein showed significantly enhanced protein expression level. The coding sequence of hvVP۲ was amplified and then identified by polymerase chain reaction (PCR) and sequencing. To achieve high-level expression of hvVP۲ protein, we optimized hvVP۲ gene base on E. coli preferred codons and synthesized the optimized gene. The synthetical gene was cloned into expression vector pET-۲۶b       and expressed in E.coli BL۲۱ (DE۳). After induction with Isopropyl-D-۱-Thiogalactopyranoside (IPTG) and optimization the conditions of expression, the hvVP۲ protein was relatively increased and identified by SDS-PAGE and Western blotting. Productive conformation can now be used for structure-based design purposes as well as structure-function relation of VP۱ protein. It is suggested that the codon optimized hvVP۲-His protein may be a useful option (but it is not enough) for developing diagnostic tests and immunization proposes.

Keywords:

hvVP۲ , IBDV , codon-optimized , protein expression