title: The interaction between bamboo mosaic virus replication protein and coat protein is critical for virus movement in plant hosts.
abstract: Bamboo mosaic virus (BaMV) is a positive-sense RNA virus belonging to the genus Potexvirus. Open reading frame 1 (ORF1) encodes the viral replication protein that consists of a capping enzyme domain, a helicase-like domain (HLD), and an RNA-dependent RNA polymerase domain from the N to C terminus. ORF5 encodes the viral coat protein (CP) required for genome encapsidation and the virus movement in plants. In this study, application of a yeast-two hybrid assay detected an interaction between the viral HLD and CP. However, the interaction did not affect the NTPase activity of the HLD. To identify the critical amino acids of CP interacting with the HLD, a random mutational library of CP was created using error-prone PCR, and the mutations adversely affecting the interaction were screened by a bacterial two-hybrid system. As a result, the mutations A209G and N210S in CP were found to weaken the interaction. To determine the significance of the interaction, the mutations were introduced into a BaMV infectious clone, and the mutational effects on viral replication, movement, and genome encapsidation were investigated. There was no effect on accumulations of BaMV CP and genomic RNAs within protoplasts; however, the virus cell-to-cell movement in plants was restricted. Sequence alignment revealed that A209 of BaMV CP is conserved in many potexviruses. Mutation of the corresponding residue in Foxtail mosaic virus CP also reduced the viral HLD-CP interaction and restricted the virus movement, suggesting that interaction between CP and a widely conserved HLD in the potexviral replication protein is crucial for viral trafficking through plasmodesmata.
authors.affiliation: Graduate Institute of Biotechnology, National Chung Hsing University, 250 Kuo-Kuang Rd., Taichung, Taiwan 40227, Republic of China.
authors.forename: Cheng-Cheng
authors.initials: CC
authors.lastname: Lee
authors.forename: Yuan-Ning
authors.initials: YN
authors.lastname: Ho
authors.forename: Rei-Hsing
authors.initials: RH
authors.lastname: Hu
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Yen
authors.forename: Zheng-Cheng
authors.initials: ZC
authors.lastname: Wang
authors.forename: Ya-Chien
authors.initials: YC
authors.lastname: Lee
authors.forename: Yau-Heiu
authors.initials: YH
authors.lastname: Hsu
authors.forename: Menghsiao
authors.initials: M
authors.lastname: Meng
mesh_terms: D000595:Amino Acid Sequence; D036022:Capsid Proteins / Q000235:genetics / Q000378:metabolism*; D004252:DNA Mutational Analysis; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D010935:Plant Diseases / Q000821:virology*; D017863:Potexvirus / Q000472:pathogenicity*; D025941:Protein Interaction Mapping; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D020798:Two-Hybrid System Techniques
chemical_list: D036022:Capsid Proteins; D050505:Mutant Proteins; D012324:RNA-Dependent RNA Polymerase