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

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

Research output: Contribution to journalArticlepeer-review

Abstract

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.
Original languageEnglish
Pages (from-to)1359-70
Number of pages12
JournalPlant physiology
Volume158
Issue number3
DOIs
Publication statusPublished - 2012

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