A 45 KDA PROTEIN ISOLATED FROM THE NODAL WALLS OF CHARA-CORALLINA IS LOCALIZED TO PLASMODESMATA

The cellular anatomy of the green alga, Chara corallina, was exploited to isolate putative plasmodesmata-associated proteins. In C. corallin a, large internodal cells are symplastically connected via intervening nodal complexes of smaller cells which have plasmodesmata in their ce ll walls. Comparison of proteins extracted from walls with plasmodesma ta (nodal complexes) with those from walls without plasmodesmata (exte rnal internodal walls) identified four putative plasmodesmata-associat ed proteins. These putative plasmodesmata-associated proteins were app roximately 95, 45, 44 and 33 kDa. A monoclonal antibody (MAB45/22) was raised against the 45 kDa putative plasmodesmata-associated protein ( CPAP45). Using immunofluorescence, this antibody colocalised with anil ine blue induced fluorescence of callose in the source cell walls. MAB 45/22 was localised to the plasmodesmata of C. corallina and, in parti cular, to the central cavity using immunogold cytochemistry. In contra st, a monoclonal antibody to callose specifically labelled the mouth o f C. corallina plasmodesmata. MAB45/22 also labelled higher plant plas modesmata.