THE LONG AND THE SHORT ISOFORM OF CELL-CAM-105 SHOW VARIANT-SPECIFIC MODIFICATIONS IN ADULT-RAT ORGANS

The cell adhesion molecule cell-CAM 105 is a member of the carcinoembr yonic antigen (CEA)-gene family and expressed on the cell surface at l east as a long (L-) and a short (S-) isoform. We have developed anti-p eptide antisera to investigate the expression patterns of both cell-CA M 105 variants in rat organs. In immunohistochemistry the S- and the L -isoform were co-localized in every tissue investigated. In contrast, the quantification of both isoforms in rat organs by a sandwich-ELISA revealed several differences in their relative expression ratio if com pared to the liver value. In submandibular gland and seminal vesicle a significant increase of the S-isoform was found, whereas in kidney th e L-isoform was overexpressed. In immunoblot analysis of kidney and se minal vesicle the two isoforms did not appear with the Mr difference w hich is deduced from their primary structures, suggesting that the two cell-CAM 105 variants are subjected in these tissues to different pos t translational modifications. (C) 1996 Academic Press, Inc.