title: Structural implications into dsRNA binding and RNA silencing suppression by NS3 protein of Rice Hoja Blanca Tenuivirus.
abstract: Rice Hoja Blanca Tenuivirus (RHBV), a negative strand RNA virus, has been identified to infect rice and is widely transmitted by the insect vector. NS3 protein encoded by RHBV RNA3 was reported to be a potent RNAi suppressor to counterdefense RNA silencing in plants, insect cells, and mammalian cells. Here, we report the crystal structure of the N-terminal domain of RHBV NS3 (residues 21-114) at 2.0 Å. RHBV NS3 N-terminal domain forms a dimer by two pairs of α-helices in an anti-parallel mode, with one surface harboring a shallow groove at the dimension of 20 Å × 30 Å for putative dsRNA binding. In vitro RNA binding assay and RNA silencing suppression assay have demonstrated that the structural conserved residues located along this shallow groove, such as Arg50, His51, Lys77, and His85, participate in dsRNA binding and RNA silencing suppression. Our results provide the initial structural implications in understanding the RNAi suppression mechanism by RHBV NS3.
authors: Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore.
authors: Xia
authors: X
authors: Yang
authors: Sook Hwa
authors: SH
authors: Tan
authors: Yee Jin
authors: YJ
authors: Teh
authors: Y Adam
authors: YA
authors: Yuan
mesh_terms: D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000821:virology; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000737:chemistry*; D016601:RNA-Binding Proteins / Q000737:chemistry*; D016415:Sequence Alignment; D029364:Tenuivirus / Q000737:chemistry* / Q000235:genetics; D014026:Nicotiana / Q000821:virology; D017361:Viral Nonstructural Proteins / Q000737:chemistry*
chemical_list: D012330:RNA, Double-Stranded; D016601:RNA-Binding Proteins; D017361:Viral Nonstructural Proteins