The Stable Association of Virion with the Triple-gene-block Protein 3-based Complex of Bamboo mosaic virus

PLoS Pathogens

Chiung-Hua Wung¹  Yau-Heiu Hsu²  Menghsiao Meng²  Yi-Jing Hung³  Hsiu-Ting Hsu³  Yuan-Lin Chou³  Ban-Yang Chang³  Jun-Yi Yang³  Yang-Hao Tseng³  Na-Sheng Lin⁴ 

[1] Biotechnology Center, National Chung-Hsing University, Taichung, Taiwan, Republic of China;Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung, Taiwan, Republic of China;Institute of Biochemistry, National Chung-Hsing University, Taichung, Taiwan, Republic of China;Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China

关键词: Virions;    Plasmid construction;    DNA cloning;    Protein extraction;    Endoplasmic reticulum;    Immunoprecipitation;    Membrane protein complexes;    Vesicles;   

DOI  :  10.1371/journal.ppat.1003405

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

The triple-gene-block protein 3 (TGBp3) of Bamboo mosaic virus (BaMV) is an integral endoplasmic reticulum (ER) membrane protein which is assumed to form a membrane complex to deliver the virus intracellularly. However, the virus entity that is delivered to plasmodesmata (PD) and its association with TGBp3-based complexes are not known. Results from chemical extraction and partial proteolysis of TGBp3 in membrane vesicles revealed that TGBp3 has a right-side-out membrane topology; i.e., TGBp3 has its C-terminal tail exposed to the outer surface of ER. Analyses of the TGBp3-specific immunoprecipitate of Sarkosyl-extracted TGBp3-based complex revealed that TGBp1, TGBp2, TGBp3, capsid protein (CP), replicase and viral RNA are potential constituents of virus movement complex. Substantial co-fractionation of TGBp2, TGBp3 and CP, but not TGBp1, in the early eluted gel filtration fractions in which virions were detected after TGBp3-specific immunoprecipitation suggested that the TGBp2- and TGBp3-based complex is able to stably associate with the virion. This notion was confirmed by immunogold-labeling transmission electron microscopy (TEM) of the purified virions. In addition, mutational and confocal microscopy analyses revealed that TGBp3 plays a key role in virus cell-to-cell movement by enhancing the TGBp2- and TGBp3-dependent PD localization of TGBp1. Taken together, our results suggested that the cell-to-cell movement of potexvirus requires stable association of the virion cargo with the TGBp2- and TGBp3-based membrane complex and recruitment of TGBp1 to the PD by this complex.

【 授权许可】

CC BY