Rice black-streaked dwarf virus P6 self-interacts to form punctate, viroplasm-like structures in the cytoplasm and recruits viroplasm-associated protein P9-1.
BACKGROUND
Rice black-streaked dwarf virus (RBSDV), a member of the genus Fijivirus within the family Reoviridae, can infect several graminaceous plant species including rice, maize and wheat, and is transmitted by planthoppers. Although several RBSDV proteins have been studied in detail, functions of the nonstructural protein P6 are still largely unknown.


RESULTS
In the current study, we employed yeast two-hybrid assays, bimolecular fluorescence complementation and subcellular localization experiments to show that P6 can self-interact to form punctate, cytoplasmic viroplasm-like structures (VLS) when expressed alone in plant cells. The region from residues 395 to 659 is necessary for P6 self-interaction, whereas two polypeptides (residues 580-620 and 615-655) are involved in the subcellular localization of P6. Furthermore, P6 strongly interacts with the viroplasm-associated protein P9-1 and recruits P9-1 to localize in VLS. The P6 395-659 region is also important for the P6-P9-1 interaction, and deleting any region of P9-1 abolishes this heterologous interaction.


CONCLUSIONS
RBSDV P6 protein has an intrinsic ability to self-interact and forms VLS without other RBSDV proteins or RNAs. P6 recruits P9-1 to VLS by direct protein-protein interaction. This is the first report on the functionality of RBSDV P6 protein. P6 may be involved in the process of viroplasm nucleation and virus morphogenesis.
State Key Laboratory for Agro-biotechnology and Ministry of Agriculture Key Laboratory for Plant Pathology, China Agricultural University, Beijing 100193, P. R. China.
Qian
Q
Wang
Tao
T
Tao
Yanjing
Y
Zhang
Wenqi
W
Wu
Dawei
D
Li
Jialin
J
Yu
Chenggui
C
Han
D002478:Cells, Cultured; D003593:Cytoplasm / Q000821:virology*; D018613:Microscopy, Confocal; D019697:Onions / Q000821:virology; D054730:Protein Interaction Domains and Motifs; D025941:Protein Interaction Mapping; D055503:Protein Multimerization; D012087:Reoviridae / Q000502:physiology*; D017384:Sequence Deletion; D014026:Nicotiana / Q000821:virology*; D020798:Two-Hybrid System Techniques; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication
D014764:Viral Proteins
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