Studying the movement of plant viruses using green fluorescent protein

Recent studies with green fluorescent protein (GFP) are providing new insights into the mechanisms of virus movement in plants, The gfp gene has been inserted into the genomes of a number of plant viruses, enabling production of either the free protein or a fusion with a virus-encoded protein, Fusion of GFP to the coat protein of potato virus X (PVX) has produced a functional virus with a GFP 'overcoat' that can be traced as it moves, Many plant viruses are known 60 use 'movement proteins' to assist in their transit through plasmodesmata, Movement protein-GFP fusions can be expressed from the parental virus or, in the absence of a full-length infectious clone, using an alternative expression vector, Such fusions retain their capacity to target plasmodesmata and are providing new information on the factors responsible for trafficking viral RNA to, and through, the plasmodesmal pore.