Journal Article

The TGB1 Movement Protein of Potato virus X Reorganizes Actin and Endomembranes into the X-Body, a Viral Replication Factory

Roberts, Alison G., Lacomme, Christophe, Tilsner, Jens, Bell, Karen, Cruz, Simon Santa, Oparka, Karl J., Linnik, Olga, Wright, Kathryn M.

2012

Overview

Potato virus X (PVX) requires three virally encoded proteins, the triple gene block (TGB), for movement between cells. TGB1 is a multifunctional protein that suppresses host gene silencing and moves from cell to cell through plasmodesmata, while TGB2 and TGB3 are membrane-spanning proteins associated with endoplasmic reticulum-derived granular vesicles. Here, we show that TGB1 organizes the PVX \"X-body,\" a virally induced inclusion structure, by remodeling host actin and endomembranes (endoplasmic reticulum and Golgi). Within the X-body, TGB1 forms helically arranged aggregates surrounded by a reservoir of the recruited host endomembranes. The TGB2/3 proteins reside in granular vesicles within this reservoir, in the same region as nonencapsidated viral RNA, while encapsidated virions accumulate at the outer (cytoplasmic) face of the X-body, which comprises a highly organized virus \"factory.\" TGB1 is both necessary and sufficient to remodel host actin and endomembranes and to recruit TGB2/3 to the X-body, thus emerging as the central orchestrator of the X-body. Our results indicate that the actin/endomembrane-reorganizing properties of TGB1 function to compartmentalize the viral gene products of PVX infection.

• Publisher: American Society of Plant Biologists
• Subject: actin / Actins / Actins - metabolism / Agrobacterium tumefaciens / Agrobacterium tumefaciens - genetics / Agrobacterium tumefaciens - metabolism / anatomy & histology / Biological and medical sciences / Cell aggregates / cell movement / Cytoplasmic Vesicles / Cytoplasmic Vesicles - metabolism / Cytoplasmic Vesicles - virology / disease reservoirs / endoplasmic reticulum / Endoplasmic Reticulum - metabolism / Endoplasmic Reticulum - virology / Fluorescent Antibody Technique / Fluorescent Antibody Technique - methods / Fundamental and applied biological sciences. Psychology / gene silencing / genes / Genes, Viral / genetics / Golgi Apparatus / Golgi Apparatus - metabolism / Golgi Apparatus - virology / hosts / Infections / Intracellular Membranes / Intracellular Membranes - metabolism / Intracellular Membranes - virology / metabolism / methods / Microscopy, Electron / Nicotiana - anatomy & histology / Nicotiana - genetics / Nicotiana - metabolism / Nicotiana - virology / pathogenicity / physiology / Phytopathology. Animal pests. Plant and forest protection / Plant cells / Plant Diseases / Plant Diseases - virology / Plant Leaves / Plant Leaves - metabolism / Plant Leaves - ultrastructure / Plant Leaves - virology / Plant physiology and development / Plant Viral Movement Proteins / Plant Viral Movement Proteins - genetics / Plant Viral Movement Proteins - metabolism / PLANTS INTERACTING WITH OTHER ORGANISMS / Plasmodesmata / Plasmodesmata - metabolism / Plasmodesmata - virology / potato protein / Potato virus X / Potexvirus / Potexvirus - genetics / Potexvirus - metabolism / Potexvirus - pathogenicity / Potexvirus - physiology / Protein Transport / Renovations / RNA / Tobacco / ultrastructure / virion / Virions / Virology / Virus Replication / Viruses