Skip to main content
SLU publication database (SLUpub)

Research article2013Peer reviewedOpen access

Dynamic localization of two tobamovirus ORF6 proteins involves distinct organellar compartments

Gushchin, Vladimir A.; Lukhovitskaya, Nina; Andreev, Dmitri E.; Wright, Kathryn M; Taliansky, Michael E.; Solovyev, Andrey G.; Morozov, Sergey Y.; MacFarlane, Stuart A.


ORF6 is a small gene that overlaps the movement and coat protein genes of subgroup la tobamoviruses. The ORF6 protein of tomato mosaic virus (ToMV) strain L (L-ORF6), interacts in vitro with eukaryotic elongation factor la, and mutation of the ORF6 gene of tobacco mosaic virus (TMV) strain U1 (U1-ORF6) reduces the pathogenicity in vivo of TMV, whereas expression of this gene from two other viruses, tobacco rattle virus (TRV) and potato virus X (PVX), increases their pathogenicity. In this work, the in vivo properties of the L-ORF6 and U1-ORF6 proteins were compared to identify sequences that direct the proteins to different subcellular locations and also influence virus pathogenicity. Site-specific mutations in the ORF6 protein were made, hybrid ORF6 proteins were created in which the N-terminal and C-terminal parts were derived from the two proteins, and different subregions of the protein were examined, using expression either from a recombinant TRV vector or as a yellow fluorescent protein fusion from a binary plasmid in Agrobacterium tumefaciens. L-ORF6 caused mild necrotic symptoms in Nicotiana benthamiana when expressed from TRV, whereas U1-ORF6 caused severe symptoms including death of the plant apex. The difference in symptoms was associated with the C-terminal region of L-ORF6, which directed the protein to the endoplasmic reticulum (ER), whereas U1-ORF6 was directed initially to the nucleolus and later to the mitochondria. Positively charged residues at the N terminus allowed nucleolar entry of both U1-ORF6 and L-ORF6, but hydrophobic residues at the C terminus of L-ORF6 directed this protein to the ER.

Published in

Journal of General Virology
2013, Volume: 94, pages: 230-240

    UKÄ Subject classification

    Plant Biotechnology
    Cell Biology
    Biochemistry and Molecular Biology

    Publication identifier


    Permanent link to this page (URI)