Transgenic plants and insect cells expressing the coat protein of arabis mosaic virus produce empty virus-like particles.

The 3' end of the RNA-2 of arabis mosaic virus (ArMV) was cloned and sequenced. The N-terminal amino acid sequence of the virion coat protein was determined by Edman degradation and the corresponding coding region identified. This gene was modified at the 5' and 3' ends by use of mismatched primers in the polymerase chain reaction (PCR), in order to facilitate the cloning of the gene, and to provide it with a methionine initiation codon. The modified cloned gene was expressed in transgenic plants, recombinant baculovirus-infected insect cells and bacteria. Both the insect cells and the plants expressing the modified coat protein gene contained empty virus-like particles (VLPs) similar to the empty virus shells found in plants infected with ArMV. These VLPs were not detected in the Escherichia coli expressing the coat protein. Analysis of the primary amino acid sequence in the ArMV coat protein revealed extensive regions of identity with that of grapevine fanleaf virus. Patterns in these identities may reflect a three-domain organization of the proteins.