Abstract
To study the involvement of Cry j 1 and Cry j 2 - the allergenic proteins of Cryptomeria japonica pollen - in pollen growth, we examined their distribution in the germinated pollen using monoclonal antibodies against both proteins. We also examined the localization of pectins and arabinogalactan proteins (AGPs) using JIM 5 and JIM 7 - monoclonal antibodies against pectins - and JIM 13 - a monoclonal antibody against AGPs - since Cry j 1 and Cry j 2 have degradation activity on pectins. In immunoblot analysis, Cry j 1 was scarcely detected in the extract from germinated pollen. Cry j 2 was found in the extracts from mature quiescent pollen grains and the germinated pollen. Immunoelectron microscopy showed little labeling of every region of the germinated pollen with the anti-Cry j 1 antibody, whereas the anti-Cry j 2 antibody labeled only the starch grains in the pollen grains and germinated pollen. In contrast, JIM 5 and JIM 7 labeled the nexine layer, and JIM 13 labeled the starch grains and other regions. Thus, the distributions of Cry j 1 and Cry j 2 in the germinated pollen were not in accord with those of pectins. Also, the localization of Cry j 2 did not coincide with that of AGP, except for the presence of both of them in the starch grains. These results suggest that Cry j 1 and Cry j 2 are not involved in pollen germination and tube growth, and that Cry j 1, which exists in the boundary region between the nexine and the intine-1 layers, may contribute to separating the intine from the exine after hydration.
