REPETITIVE PROTEIN ANTIGENS OF TRYPANOSOMA-CRUZI HAVE DIVERSE INTRACELLULAR LOCATIONS

We previously identified by immunoscreening Trypanosoma cruzi cDNA lib raries a group of proteins containing long stretches of tandem repeats . The goal of the current project was to gain insight into the functio ns of these proteins through ultrastructural analyses consisting of we stern blotting and electron microscopic localization studies. By compa ring western blots of total parasite lysate and different fractions of T. cruzi, we found that 3 of the repetitive antigens are exclusively associated with the parasite membrane, or cytoskeleton, or both. One o f the 4 repetitive antigens studied has some association with the memb rane or cytoskeleton but also appears to be free in the cytosol. In im munoelectron microscopic studies, the 4 repetitive antigens were detec ted in different intracellular locations. One of the proteins is locat ed between the flagellum and parasite body, the second has a nuclear d istribution, the third is associated with the cell membrane, and the f ourth is dispersed throughout the cytoskeletal network. These findings suggest that despite the general structural similarities of these rep etitive proteins, they may serve different cellular functions.