Mechanism for Intercellular Movement of Potato Virus X

Oklahoma State University, Stillwater OK

Investigators

Abstract

The triple gene block of PVX is a genetic module that is conserved among members of the potex-, carla-, furo-, and hordeivirus families and is required for virus transport through plasmodesmata. The PVX triple gene block produces three proteins named the 25K, 12K and 8K proteins. While several properties of these proteins have been identified the exact contribution of these proteins to the movement process has not been determined yet. The project is designed to identify the specific functions of the PVX proteins, to analyze how they interact with each other to promote virus movement, and to determine how they interact with the host cell to facilitate virus movement. Plasmids containing the PVX movement protein genes fused to the GFP gene were prepared and used to bombard tobacco leaves. Movement of proteins between cells is viewed by fluorescence microscopy. Plasmids will be bombarded to transgenic tobacco expressing the PVX triple gene block proteins to study the effects of viral protein-protein interactions on viral protein movement and subcellular targetting. This approach has been quite valuable because it has provided an opportunity to view some protein-protein interactions that were not detected previously in studies which utilized microinjection to deliver proteins into cells. Secondly, mutational analysis will be conducted using the PVX 25K protein to identify domains that function in protein movement and protein-protein interactions. These studies will be combined with innovative approaches to analyze virion assembly in vivo and to determine the role of virions in cell-to-cell movement.