Background: The advent of recombinant DNA technology has facilitated heterologous expression of proteins from various sources in different host systems including Escherichia coli. If a plant virus coat protein is expressed in the bacterium it can be used as the antigen for antibody preparation. Such a recombinant antigen preparation can be particularly useful where equipment such as ultracentrifuge is unavailable to purify virus particles to use as the antigen for conventional antibody preparation.
Objectives: Heterologous protein expression and purification of the full length Potato virus Y (PVY) coat protein (CP) from isolate pot187 (an affiliate of strain N) to be used as an antigen was the aim of the study.
Materials and methods: Reverse transcription Polymerase Chain Reaction (RT-PCR) was carried out to amplify an 801 bp fragment of the CP gene from PVY-infected potato leaves. The amplicon was cloned into pGEM-T Easy. The cloned fragment was restricted by BamHI + SacI and the purified fragment was cloned into the expression vector pET21a(+) which was restricted with the same enzymes. The generated plasmid was introduced into E. coli strain RosettaTM. The expression was induced with isopropyl-β-D-thiogalactopyranoside (IPTG) and its protein content was subjected to SDSPAGE and western blotting.
Results: SDS-PAGE analysis of protein from the induced bacteria showed a ~35 KDa protein corresponding to PVY CP. Expression of the recombinant protein was confirmed by anti-His anitibody.
Conclusions: The full-length cDNA of PVY-CP was amplified from the infected potato leaves. The cDNA was heterologously expressed in E. coli. The produced recombinant CP can be used as an antigen to generate polyclonal antibody.
Keywords: Cloning; Coat protein; E. coli; Expression; PCR; PVY-pot187; Recombinant.