9317368 Beachy Many plant viruses direct the synthesis of one or more proteins required for the spread of infection from the initial; site to adjacent cells. In the case of tobacco mosaic virus the movement protein responsible for spread of the virus has been identified and extensively studied. Nevertheless, the cellular and molecular mechanism responsible for the spread are not well understood. Previous studies have suggested that the ability of the movement protein to facilitate virus movement is the result of a combination of several functions or characteristics: 1) association with plasma membranes; 2) association with cell walls; 3) association with plasmodesmata with or without the formation of fibrous material in the channel; 4) modification of the plasmodesmata size exclusion limit; 5) formation of large, soluble complex perhaps including RNA. The proposed research will determine which functions are required for biological activity. Complementation of nonfunctional mutants of the movement protein will be used to identify regions of the protein that may be responsible for separate functions. A combination of in vitro and in vivo studies will then be used to identify which functions are associated with the mutated sequences. %%% The results of the study on the function of the virus movement protein will lead to a better understanding of how viral infections spread in plants. In turn this may lead to novel methods in preventing plant diseases. In addition, because the movement protein interacts with plasmodesmata, the knowledge obtained will lead to a greater understanding of intercellular communication in plants ***
