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Title: Mutational analysis of PVX TGBp3 links subcellular accumulation and protein turnover

Potato virus X (PVX) TGBp3 is required for virus cell-to-cell transport, has an N-terminal transmembrane domain, and a C-terminal cytosolic domain. In the absence of virus infection TGBp3:GFP is seen in the cortical and perinuclear ER. In PVX infected cells the TGBp3:GFP fusion is also seen in the nucleoplasm indicating that events during PVX infection trigger entry into the nucleus. Mutational analysis failed to identify a nuclear targeting domain. Mutations inhibiting TGBp3 association with the ER and inhibiting virus movement did not block TGBp3:GFP in the nucleoplasm. A mutation disrupting the N-terminal transmembrane domain of TGBp3 caused the fusion to accumulate in the nucleus indicating that nuclear import is regulated by ER interactions. Tunicamycin, an ER-stress inducing chemical, caused lower levels of GFP and TGBp3:GFP to accumulate in virus infected protoplasts. MG115 and MG132 were used to demonstrate that wild-type and mutant TGBp3:GFP fusions were degraded by the 26S proteasome. These observations are consistent with an ER-associated protein degradation (ERAD) pathway suggesting that PVX TGBp3, similar to aberrant ER proteins, is translocate to the cytoplasm for degradation. Nuclear accumulation of mutant and wild-type TGBp3:GFP is independent of other PVX proteins and may be another feature of an ERAD pathway.
Authors:
;  [1] ;  [2]
  1. Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, Oklahoma 74078 (United States)
  2. Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, Oklahoma 74078 (United States), E-mail: Verchot.lubicz@okstate.edu
Publication Date:
OSTI Identifier:
21140990
Resource Type:
Journal Article
Resource Relation:
Journal Name: Virology; Journal Volume: 375; Journal Issue: 1; Other Information: DOI: 10.1016/j.virol.2008.01.030; PII: S0042-6822(08)00066-4; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; BIOLOGICAL STRESS; CYTOPLASM; MUTANTS; MUTATIONS; PLANT CELLS; POTATOES; PROTEINS; VIRUSES