Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: April 8, 1999
Publication Date: N/A
Technical Abstract: Cucumber mosaic virus (CMV), the type member of the genus Cucumovirus, belongs to the family Bromoviridae. CMV has a divided genome consisting of three positive stranded RNAs. While both RNAs 1 and 2 encode single proteins involved in viral replication, RNA 3 encodes two proteins essential for virus movement and encapsidation. Since CMV has the widest host range among the plant viruses, we initiated investigations into the development of CMV as a viral-based vector. A CMV strain (CMV-Ix) originally isolated from Ixora had previously been cloned and the transcripts generated therefrom had been shown to be infectious. To transform CMV-Ix into a gene vector, genome component RNA 3 was split into two inter-dependent sub-components, RNA 3A and RNA 3B. In RNA 3A, the open reading frame of movement protein (MP) was replaced by a reporter gene green fluorescent protein (GFP). In RNA 3B, the coat protein (CP) gene was seliminated and a multiple cloning site (MCS) was created for foreign gene insertion. Each sub-component alone is defective and relies on its companion sub-component to restore full RNA 3 function. Preliminary results suggest that the engineered virus can move from cell to cell in the inoculated leaf and can enter the minor veins of the inoculated leaf. However, intermolecular recombination between RNA 3A and 3B occurred frequently, preventing efficient expression of foreign gene(s) in non-inoculated leaves. Modifications and further evaluations are being undertaken to improve the vector as a gene delivery system for the expression of foreign gene products and for epitope display and vaccine production.