Heterologous Expression of Potato Virus Y Coat Protein, Isolate Pot187

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.

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.

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.

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.

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.