CHARACTERIZATION OF A POLYMORPHIC PROTEIN LOCALIZED TO VASCULAR EPITHELIUM IN BOTRYLLUS-SCHLOSSERI - ROLE IN TUNIC SYNTHESIS

To develop an antibody-based screen for epitopes involved in botryllid historecognition, BALB/c mice were immunized with whole Botryllus sch losseri colonies. Resulting monoclonal antibodies were screened for al pha or beta fusibility types using enzyme-linked immunosorbent assay ( ELISA) and immunohistochemical staining. One monoclonal antibody (109) that recognized a polymorphic epitope was further analyzed by Western blotting. It binds a species-specific epitope localized to the atrial siphon and blood vessels. The epitope does not cosegregate with fusib ility type. A complementary DNA clone encoding this antigen contains a n endoplasmic reticulum retention motif. Polymorphism observed on West ern blots was confirmed by Northern blot analysis. This antigen provid es a new polymorphic marker that may be useful in studies of tunic for mation.