THE MOVEMENT PROTEINS OF COWPEA MOSAIC-VIRUS AND CAULIFLOWER MOSAIC-VIRUS INDUCE TUBULAR STRUCTURES IN PLANT AND INSECT CELLS

The movement proteins (MP) of cowpea mosaic virus and cauliflower mosa ic virus (CaMV) are associated with tubular structures in vivo which p articipate in the transmission of virus particles from cell to cell. B oth proteins have been expressed in plant protoplasts and insect cells . In all cases, immunofluorescent histochemistry showed that the MPs a ccumulate intracellularly as tubular extensions projecting from the ce ll surface. Additionally, electron microscopy revealed intracellular M P aggregates in CaMV MP-expressing cells. The data presented establish common features for the tubule-forming MPs: no other virus gene produ cts are required for tubule formation and unique plant components (e.g . plasmodesmata) are not essential for tubule synthesis.