Abstract

Live-cell fluorescence microscopy was used to investigate the third triple gene block protein (TGB3) of potato mop-top pomovirus and its role in assisted targeting of TGB2 to plasmodesmata (PD). Wild-type and mutant TGB3 proteins were expressed under the control of the 35 S promoter or from a virus reporter clone. Assisted targeting of TGB2 to PD was optimal when the proteins were expressed from a bicistronic plasmid in the relative ratios expected in a virus infection, suggesting that excess TGB3 inhibited PD localisation. Contrary to the generally accepted view, bimolecular fluorescence complementation showed that the TGB3 N terminus is located in the cytosol. Mutational analysis to dissect TGB3 sub domain functions showed that PD targeting was mediated by a composite signal comprising an ER-lumenal tyrosine-based motif and the C-terminal transmembrane domain. Mutation of either of these domains also abolished cell-to-cell movement of the virus. The results are discussed in the context of TGB3 membrane topology. (C) 2010 Elsevier Inc. All rights reserved.

Keywords

Triple gene block; Hordei-like virus movement proteins; Bimolecular fluorescence complementation; Green fluorescent protein; Red fluorescent protein

Published in

Virology
2010, Volume: 402, number: 1, pages: 41-51
Publisher: ACADEMIC PRESS INC ELSEVIER SCIENCE

UKÄ Subject classification

Forest Science
Agricultural Science


Publication identifier

DOI: https://doi.org/10.1016/j.virol.2010.03.008

Permanent link to this page (URI)

https://res.slu.se/id/publ/60978