M. Erhardt et al., The first triple gene block protein of peanut clump virus localizes to theplasmodesmata during virus infection, VIROLOGY, 264(1), 1999, pp. 220-229
The subcellular localization of the first triple gene block protein (TGBp1)
of peanut clump pecluvirus (PCV) was studied by subcellular fractionation
and immunogold cytochemistry using TGBp1-specific antibodies raised against
a fusion protein expressed in and purified from bacteria. In the inoculate
d and apical leaves of virus-infected Nicotiana benthamiana, TGBp1 localize
d to the cell wall and P30 fractions. Electron microscopy of immunogold-dec
orated ultrathin sections of the infected leaf tissue revealed TGBp1-specif
ic labeling of the plasmodesmata joining mesophyll cells. In longitudinal s
ections of the plasmodesmata, the TGBp1-specific labeling was most commonly
associated with the plasmodesmal collar region. In transgenic N. benthamia
na, which constitutively expressed TGBp1, no TGBp1-specific immunogold labe
ling of plasmodesmata was observed, but plasmodesmata were gold decorated w
hen the transgenic plants were infected with a TGBp1-defective PCV mutant,
indicating that factors induced by the virus infection target and/or anchor
the transgene TGBp1 to the plasmodesmata. (C) 1999 Academic Press.