Expression and subcellular location of NSm protein of Tomato spotted wilt virus in plant and insect cells

Abstract:

Abstract:［Objective］Expression and subcellular location of NSm protein of Tomato spotted wilt virus were studied using plant and insect cells． ［Methods］First，the NSm gene，located on the ambisense M RNA segment of tomato spotted wilt virus，was cloned into the pCHF3 vector which includes a GFP gene． Agrobacterium-mediated transient expression from N．benthamiana leaves was used to study the location of NSm in plant cells． Second，to test whether plant-specific components were involved in tubule formation，the NSm gene was also expressed in a heterologous expression system，i.e.，insect cells. T. ni (Tn) cells were infected with a recombinant baculovirus expressing the NSm gene．［Results］NSm-GFP fusion proteins diffused in the tobacco epidermal cells and were located at the edge of the cell walls． These proteins can also form discontinuous green fluorescent spots at the plasmodesmata，which were sometimes present in pairs between two neighboring cells． However，GFP proteins expressed alone distributed evenly around the cell wall and in the nucleus． In the entomic Tn cells，NSm proteins formed a large number of tubular structures extending from the surface．Conclusion］These findings suggest that NSm protein target the plasmodesmata specifically in plant cells，and they also could form tubular structures on the surface when expressed in entomic Tn cells．