Three-dimensional architecture of virus-packed tubule

When rice dwarf virus (RDV), a member of the Reoviridae family, infects leafhopper cells, formation of protruding tubules composed of nonstructural viral protein Pns10 can be observed. We examined the three-dimensional (3D) structure of these tubules containing RDV particles using electron tomography. The thin section of RDV-infected leafhopper vector cells in monolayers was subjected to double-tilt tomography. The tomographic 3D map provides a more reliable estimation of the real dimensions of the structure compared with the 2D image of the thin section. Docking of particle models made from atomic coordinates of RDV into the tomogram revealed that the inner diameter of the tubule was close to the outer diameter of the RDV particle. Fourier-transform of the reconstituted tubule image from the purified Pns10 protein in vitro revealed a helical structure of the tubule.