Hypothesis on particle structure and assembly of rice dwarf phytoreovirus: interactions among multiple structural proteins.

To study the morphogenesis and packaging of rice dwarf phytoreovirus (RDV), the interactions among multiple structural proteins were analysed using both the yeast two-hybrid system and far-Western blotting analysis. The following protein-protein interactions were observed. P3 (major core protein) bound to itself as well as to P7 (nucleic acid-binding protein) and P8 (major outer capsid protein). P7 bound to P1 (RNA-dependent RNA polymerase) and P8, in addition to P3. Based on these findings, we hypothesize that the core shell structure is based on P3-P3 interactions and that P7 has the ability to bind to multiple structural proteins as well as to genomic RNAs during viral particle assembly. Based on the observed protein-protein interactions and on computer-aided analysis of the numbers of structural proteins per particle, possible RDV assembly events are proposed.