The movement protein NSm of tomato spotted wilt tospovirus (TSWV): RNA binding, interaction with the TSWV N protein, and identification of interacting plant proteins

The nonstructural NSm protein of tomato spotted wilt tospovirus (TSWV) repr esents a putative viral movement protein involved in cell-to-cell movement of nonenveloped ribonucleocapsid structures. To study the molecular basis o f NSm function, we expressed the protein in Escherichia coil and investigat ed protein-protein and protein-RNA interactions of NSm protein in vitro. NS m specifically interacts with TSWV N protein and binds single-stranded RNA in a sequence-nonspecific manner. Using NSm as a bait in a yeast two-hybrid screen, we identified two homologous NSm-binding proteins of the DnaJ fami ly from Nicotiana tabacum and Arabidopsis thaliana.