It has long been known that plasmodesmata are involved in the symplastic transport of solutes between adjacent plant cells. The overall aim of this project is to study the compositional, structural and functional organization of plasmodesmata in higher plants. Recent data have suggested that proteins present in plasmodesmata may resemble connexin proteins present in the gap junctions of animal cells. Gap junctions are involved in the symplastic movement of ions and perhaps small molecules between animal cells. The hypothesis being tested in this proposal is that plant connexins reside in plasmodesmata and are involved in intercellular transport processes. The primary thrust of this project is to produce and purify a panel of monospecific antibodies directed against protein motifs present in a putative plant connexin that has already been obtained from a cDNA expression library from Arabidopsis. The antibodies will be used in ultrastructural immunolocalizations, with the aim of demonstrating their specific distribution in or around plasmodesmata. Later, the antibodies will be used in a fluorescent dye transport assay, where their specific associations with plasmodesmatal components are expected to block intercellular movement of the fluorochrome. Collectively, these studies will contribute to our understanding about the structural organization and functional roles connexin-like proteins in plasmodesmata.
