Intracellular and intercellular movement of maize streak geminivirus V1 and V2 proteins transiently expressed as green fluorescent protein fusions.
Transient expression of the maize streak geminivirus virion-sense proteins V1 and V2 (movement protein, MP, and coat protein, CP, respectively) in maize leaves allowed investigation of their roles in inter- and intracellular movement. Bombardment of a construct directing expression of a V1:green fluorescent protein (GFP) fusion product resulted in significantly increased spread of fluorescence from the bombarded cell to adjacent cells compared to that obtained following expression of free GFP. A mutant V1:GFP fusion product exhibited markedly less movement than the V1:GFP protein. Thus, the MSV V1 protein moves from cell to cell in the absence of other viral proteins. However, V1:GFP did not localize to plasmodesmata in maize or tobacco leaves although a tobacco mosaic virus MP:GFP fusion protein was shown to do so in tobacco. The CP:GFP fusion product targeted exclusively to the nucleus and did not move from cell to cell or exit the nucleus when expressed alone. When coexpressed with V1, some CP:GFP fluorescence was seen at the cell periphery in a proportion of cells, but in no case was cell-to-cell movement of CP:GFP detected. The likely roles of V1 and CP in MSV movement are discussed.
Department of Plant Sciences, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
G
G
Kotlizky
M I
MI
Boulton
C
C
Pitaksutheepong
J W
JW
Davies
B L
BL
Epel
D002213:Capsid / Q000235:genetics / Q000378:metabolism*; D017791:Geminiviridae / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D049452:Green Fluorescent Proteins; D007424:Intracellular Fluid / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D053830:Plant Viral Movement Proteins; D010947:Plants, Toxic; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D003313:Zea mays / Q000821:virology*
D008164:Luminescent Proteins; D053830:Plant Viral Movement Proteins; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D049452:Green Fluorescent Proteins