Intramolecular complementing mutations in tobacco mosaic virus movement protein confirm a role for microtubule association in viral RNA transport.
The movement protein (MP) of Tobacco mosaic virus (TMV) facilitates the cell-to-cell transport of the viral RNA genome through plasmodesmata (Pd). A previous report described the functional reversion of a dysfunctional mutation in MP (Pro81Ser) by two additional amino acid substitution mutations (Thr104Ile and Arg167Lys). To further explore the mechanism underlying this intramolecular complementation event, the mutations were introduced into a virus derivative expressing the MP as a fusion to green fluorescent protein (GFP). Microscopic analysis of infected protoplasts and of infection sites in leaves of MP-transgenic Nicotiana benthamiana indicates that MP(P81S)-GFP and MP(P81S;T104I;R167K)-GFP differ in subcellular distribution. MP(P81S)-GFP lacks specific sites of accumulation in protoplasts and, in epidermal cells, exclusively localizes to Pd. MP(P81S;T104I;R167K)-GFP, in contrast, in addition localizes to inclusion bodies and microtubules and thus exhibits a subcellular localization pattern that is similar, if not identical, to the pattern reported for wild-type MP-GFP. Since accumulation of MP to inclusion bodies is not required for function, these observations confirm a role for microtubules in TMV RNA cell-to-cell transport.
Boyko
Vitaly
V
Friedrich Miescher Institute for Biomedical Research, Novartis Research Foundation, CH-4058 Basel, Switzerland.
Ashby
Jamie Alan
JA
Suslova
Elena
E
Ferralli
Jacqueline
J
Sterthaus
Oliver
O
Deom
Carl M
CM
Heinlein
Manfred
M
D001692:Biological Transport; D005816:Genetic Complementation Test; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000502:physiology*; D009154:Mutation; D018515:Plant Leaves / Q000378:metabolism / Q000821:virology; D053830:Plant Viral Movement Proteins; D011523:Protoplasts / Q000378:metabolism / Q000821:virology; D012367:RNA, Viral / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D014026:Nicotiana / Q000378:metabolism / Q000821:virology; D014027:Tobacco Mosaic Virus / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism*
D008164:Luminescent Proteins; D053830:Plant Viral Movement Proteins; D012367:RNA, Viral; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D049452:Green Fluorescent Proteins