BEAN DWARF MOSAIC GEMINIVIRUS MOVEMENT PROTEINS RECOGNIZE DNA IN A FORM-SPECIFIC AND SIZE-SPECIFIC MANNER

Plant viral movement proteins mediate the cell-to-cell movement of nuc leic acids. This involves either a direct interaction between the vira l movement protein and the nucleic acid or an indirect interaction inv olving host factors. The bipartite geminiviruses possess two movement proteins, BV1 and BC1, that coordinate movement of viral DNA across nu clear and plasmodesmal boundaries, respectively. Here, we demonstrate that both BV1 and BC1 interact directly with DNA and, in addition, tha t they have the unique property to recognize DNA on the basis of form and size rather than sequence. This is a novel feature for plant virus movement proteins and raises the possibility that BV1 and BC1 may be determinants of genome size in the bipartite geminiviruses.